Oracle Answers

Copyright © 2011, Oracle. All rights reserved.

Introduction to the Oracle Academy

2



What Will I Learn?

Objectives

In this lesson, you will learn to:

• Give examples of jobs, salary and opportunities

available that could result from participating in the

Academy

• Understand how participating in the Academy can

help you to realize these opportunities

3



Why Learn It?

Purpose

A passage from a book may get you interested in reading

the whole text. A movie trailer or preview may make you

curious enough to see the film. A food sampled at the

supermarket may result in a product purchase.

The Oracle Academy aims to give you a peek at some of

the skills required in the professional workplace and the

opportunities that could result from learning them.

4



Tell Me / Show Me

Questions to Consider

What kind of career in business or in the technology

industry do you want to have? What types of jobs are

you interested in? What options are you preparing

yourself for?

5



Tell Me / Show Me

Considerations

Labor statistics report a steady increase in

employment opportunities for database and

Internet-trained personnel in many fields,

including:

- Publishing

- Trade

- Business Services

- Membership Organizations

As their Web presence grows in importance

for more and more organizations, there is a

growing demand for skilled professionals to

develop and support Web applications.

6



Tell Me / Show Me

Survey

Jobs and salaries in the IT field*

Group Average

Starting

Average Base

Salary

Business

programmers

54,351 67,382

Communications 44,967 52,945

Computer staff 26,105 29,986

Database

professionals

46,327 53,456

Management 63,470 75,317

Support

professionals

32,926 39,828

* Sample State = California

Statistics

7



Tell Me / Show Me

Required Education for IT

Positions

Today, so many jobs require an

associate’s degree or higher

degree. In technology, many

opportunities ask for industry-

recognized certifications.

Physical working boundaries

have allowed employers to hire

employees working from remote

locations which has broadened

the pool of candidates. Your

education goals are important in

helping you get into a career that

you enjoy.

8



Tell Me / Show Me

The Oracle Academy

Introducing...

The Oracle Academy

Teacher-led/project-driven

+

I.T. industry-recognized certification

+

Higher-Education options

=

21st-century economic viability

9



Tell Me / Show Me

Possible Career Path 1

Title: Entry-Level Database Engineer

Maintain data integrity; run database queries

Requirements: 0 - 2 yrs. + bachelor's degree

Salary: $25,000 - $50,000 USD

Title: Database Administrator (DBA)

Conduct extensive database analysis and problem solving; maintain database configuration and ensure data accuracy


Salary: $65,000 - $90,000 USD

Title: Senior Database Administrator

Develop, implement, enhance, support, and maintain database

Requirements: 5+ yrs. + bachelor's degree

Salary: $100,000+ USD

MOVIE

sdm_s01_l01_a05.swf

Oracle Academy Preparation for a Career

10



Tell Me / Show Me

Possible Career Path 2

Title: Junior Consultant

Install and troubleshoot client systems


Salary: $35,000 - $45,000 USD

Title: Sales Consultant

Assist sales representatives with system presentations and client needs assessment


Salary: $50,000 - $90,000 USD

Title: Project Manager

Manage system design, engineering, implementation, and integration; initiate and maintain partner relationships

Requirements: 4+ yrs. + bachelor's degree

Salary: $90,000+ USD

MOVIE

sdm_s01_l01_a06.swf

Oracle Academy Preparation for a Career (continued)

11



Tell Me / Show Me

The Oracle Academy Database Design and

Programming with SQL Course

This Oracle Academy course is the first of two

courses available to you. This course begins

with topics covering:

• Entity relationship modeling, database

design, development, and normalization

• History of the database, evolution of

computing

• Business skills: presentations, case

studies

MOVIE

sdm_s01_l01_a07.swf

12



Tell Me / Show Me

The Oracle Academy Database Design

and Programming with SQL Course

(continued)

This course then continues on to cover

topics including:

• SQL (structured query language) “The

language of the database”

• Accessing data with SQL

• Data definition, manipulation and

control languages

• Transaction control

• Building applications

• Business skills: interviewing, creating a

career portfolio

13



Tell Me / Show Me

The Oracle Academy Database Programming with PL/SQL

Course

This Oracle Academy course is the second of two courses

available to you. Topics covered in this course include:

• PL/SQL, a procedural language extension to SQL

• Procedural programming structures such as variables,

constants, and parameters

• Conditional control statements including IF and CASE

• Iterative control statements including LOOP, WHILE, and

FOR

• Handling exceptions

• Creating procedures, functions, packages, and triggers

14



Tell Me / Show Me

Oracle Certifications

The Oracle Academy can prepare you for 2 certifications.

• Oracle Database SQL Certified Expert

1Z0-047: Oracle Database SQL Expert

• Oracle PL/SQL Developer Certified Associate(Completion of 1 SQL and 1 PLSQL Exam)

1Z0-051 Oracle Database 11g: SQL Fundamentals I

1Z0-007 Introduction to Oracle9iSQL

1Z0-047 Oracle Database SQL Expert

1Z0-147: Programming with PL/SQL

1Z0-144: Oracle Database 11g

Program with PL/SQL

SQ

LP

L/S

QL

15



Summary

Objectives Summarized

In this lesson, you have learned to:

• Give examples of jobs, salary and opportunities

available that could result from participating in the

Academy

• Understand how participating in the Academy can help

you to realize these opportunities

16



Summary

Practice Guide

The link for the lesson practice guide can be found in the course

resources in Section 0.


Data vs. Information

2



What Will I Learn?

Objectives


• Distinguish between data and information and provide

examples of each

• Describe and give an example of how data becomes

information

3



Why Learn It?

Purpose

All kinds of information (school records, mobile telephone

records, ring tone downloads, grocery purchases) are

stored in databases. We interact with databases every

day, consciously or unconsciously.

It is important to understand what is stored in a database

and what can be retrieved from it.

4



Why Learn It?

Data Compared to

Information

If you work in the information-

technology industry, it is

essential to understand how

data is modeled and stored in

a database.

If you work in any other

industry, you will most likely

have to work with data stored

somewhere on a computer

and probably be required to

use data in your job to create

reports and/or make

decisions.

Data: Lunch Room Data

Information:

This report will tell us what our

best-selling lunch items are.

5



Tell Me / Show Me


The words "data" and "information" are often used as if they are synonyms. Nevertheless, they have different meanings.

Data: Raw material, from which you can draw conclusions. Facts from which you can deduce new facts.

Information: knowledge, intelligence, a particular piece of data with a special meaning or function. Information is often the result of combining, comparing and performing calculations on data.

sdm_s03_l04_a03

6



Tell Me / Show Me

Data vs. Information (continued)

Whenever a student, teacher, administrator (or any person

using a computer) interacts with a website, pieces of data

are collected. The website application may be unique to that

school or company, but what happens in the background?

7



Tell Me / Show Me

Data vs. Information (continued)

Think about test scores, for example.

In one class, if every student

receives a numbered score, the

scores can be calculated to

determine a class average. The class

averages can be calculated to

determine the school average. The

Oracle database software will

transform recorded/stored data and

statistics into useful pieces of

information.

Data: Each student’s test score is

one piece of data

Information: The class’ average

score or the school’s average score

Data in… Information out…

1997 $1,000,000

1998 $2,000,000

…Next year’s budget

“Article VI prohibits

use of School

property for…”

312 graduates

98% of students

pass the

Math exam…

Student test

scores were…

Regulatory

Implementation

…Where are they

going?

By how much?

…Class average

or school average

DATABASE

8



Tell Me / Show Me

What is a Database?

• A database is a centralized and structured set of

data stored on a computer system.

• It provides facilities for retrieving, adding,

modifying and deleting the data when required.

• It also provides facilities for transforming

retrieved data into useful information.

• A database is usually managed by a Database

Administrator (DBA).

9



Tell Me / Show Me

Documents, Pictures,

Video and Sound

Within most modern

databases, you can

store and retrieve a wide

variety of data and

documents. Inside the

database, data is stored

in a “raw” form. When

this raw data is queried

or retrieved, it is

transformed into more

useful output or

information.

Operational Media-rich

External

Decision support Documents

Different Data/Sources

10



Tell Me / Show Me

Question: What does a

database have to do with

my everyday life?

Answer: More than you

may realize...

A lot of websites that you

visit are driven by a

database.

11



Tell Me / Show Me

Question: If you had one of

the jobs listed below, how

might you use a database?

(1) mechanic in an auto-repair

shop

(2) taxi driver

(3) landscape gardener

Database

12



Tell Me / Show Me

Question: Have you ever

returned an item to a store

without a receipt?

What information did you have

to provide?

Were you able to return the

item?

sdm_s03_l04_a02

13



Tell Me / Show Me

Terminology

Key terms used in this lesson include:

Data

Information

Database

14



Summary


In this lesson, you have learned how to:

• Distinguish between data and information and provide

examples of each

• Describe and give an example of how data becomes

information

15



Summary

Practice Guide

The link for the lesson practice guide can be found in the

course resources in Section 0.


History of the Database

2



What Will I Learn?

Objectives


• Describe the evolution of the database and give an example of its role in the business world

• Name important historical contributions in database development and design

• Describe the database development process

3



Why Learn It?

Purpose

History provides perspective for where we are today in

information technology. The next time you use your

computer, your video gaming system, or your smart phone,

you will realize how far we’ve come to get to this point and

what events brought us here.

Data Modeling is the first step in database development.

This lesson includes an overview of what the rest of this

course is about.

4



Tell Me / Show Me

History of the Database Timeline

1960s: Computers become cost effective for private companies along with

increased storage capability.

1970-72: E. F. Codd proposes the relational model for databases, disconnecting

the logical organization from the physical storage.

1976: P. Chen proposes the entity relationship model (ERM) for database design.

Early 1980s: The first commercially-available relational database systems start to

appear at the beginning of the 1980s with Oracle Version 2.

Mid-1980s: SQL (structured query language) becomes "intergalactic standard."

5



Tell Me / Show Me

History of the Database Timeline (continued)

Early 1990s: An industry shakeout begins with fewer surviving companies. Oracle survives.

Mid-1990s: Kaboom! The usable Internet/World Wide Web (WWW) appears. A mad scramble ensues to allow remote access to computer systems with legacy data.

Late 1990s: The large investment in Internet companies helps create a tools market boom for Web/Internet/DB connectors.

Early 21st century: Solid growth of DB applications continues. Examples: commercial websites (yahoo.com, amazon.com), government systems (Bureau of Citizenship and Immigration Services, Bureau of the Census), art museums, hospitals, schools, etc.

6



Tell Me / Show Me

Question: What does a

database have to do

with data modeling?

Data modeling is the first

part of the database

development process.

Conceptual Data

Modeling

Database Design

Database Build

Entity Relationship

Table Definitions

Index, View, Cluster

Operational Database

Strategy

Analysis

Design

Build

Business Information Requirements

Database Development Process

7



Tell Me / Show Me

Database Development Process Begins With Business

Information Requirements

EXAMPLE

Here is a set of information requirements:

I manage the Human Resources Department for a large company. We need to keep

information about each of our company’s employees. We need to track each employee's

first name, last name, job or position, hire date and salary. For any employees on

commission, we also need to track their potential commission. Each employee is

assigned a unique employee number.

Our company is divided into departments. Each employee is assigned to a department --

for example, accounting, sales or development. We need to know the department

responsible for each employee and the department location. Each department has a

unique number.

Some of the employees are managers. We need to know each employee's manager and

the employees each manager manages.

8



Tell Me / Show Me

Database Development

Process

An entity relationship

model should accurately

model the organization’s

information needs and

support the functions of

the business.

EXAMPLE

The following entity relationship model represents the

information requirements of the Human Resources

Department.

DEPARTMENT

# numberassigned to

responsible for

managed bythe manager of

# number

* first name

* last name

* hire date

o job

o salary

EMPLOYEE

9



Tell Me / Show Me

Database Development Process (continued)

In database design, the information requirements reflected in the

entity relationship model are mapped into a relational database

design using a table instance chart. A table instance chart has the

following components:

• Table name

• Column names

• Keys: a primary key (PK) is the unique identifier for each row of

data; a foreign key (FK) links data from one table to another by

referring to a column in that other table

• Nulls: indicate if the columns must have a value (mandatory)

• Unique: indicates if the value in the column is unique within the

table

• Datatype: refers to the format and definition of the data in each

column

10



Tell Me / Show Me

Database

Development

Process

(continued)

SQL commands

are used to build

the physical

database.

SQL>CREATE TABLE department

2 (deptno NUMBER(5) NOT NULL PRIMARY KEY,

3 name VARCHAR2(25) NOT NULL,

4 loc VARCHAR2(30) NOT NULL);

SQL>CREATE TABLE employees

2 (empno NUMBER(9) NOT NULL PRIMARY KEY,

3 fname VARCHAR2(15) NOT NULL,

4 lname VARCHAR2(20) NOT NULL,

5 job VARCHAR2(15),

6 hiredt DATE NOT NULL,

7 sal NUMBER(9,2),

8 comm NUMBER(9,2),

9 mgr NUMBER(2) REFERENCES EMPLOYEES

10 deptno NUMBER(5) REFERENCES DEPARTMENT);

DATABASE BUILD

Structured Query

Language (SQL)

is used to create

and manipulate

relational

databases.

11



Tell Me / Show Me

Terminology


Datatype

Foreign key (FK)

Nulls

Primary key (PK)

Table instance chart

Unique

12



Summary



• Describe the evolution of the database and give an example of its role in the business world

• Name important historical contributions in database development and design

• Describe the database development process

13



Summary

Practice Guide

The link for the lesson practice guide can be

found in the course resources in Section 0.


Major Transformations in Computing

2



What Will I Learn?

Objectives


• Relate major transformations enabled by changes in

computing to day-to-day activities

• Define and give an example of these terms: hardware,

operating system, software

• Identify examples of e-businesses that use database

software and explain how it is essential to their success

• Explain the overall mission of the Oracle Corporation

3



Why Learn It?

Purpose

History provides perspective for where we are today in

information technology.

If we know where we have come from, it is easier to

understand where we are today, and where we are likely

to go in the future.

The first job you do after you graduate may not exist in 20

years’ time!

4



Tell Me / Show Me

Key Terms

• Hardware: the physical “bits and pieces” of a

computer, for example keyboard, screen, mouse, disk

drive, memory

• Software: programs (sets of instructions) which tell

the hardware what to do.

• Operating system: a software program which directly

controls and manages the hardware, for example

Microsoft Windows.

• Application: a software program which carries out

specific tasks on behalf of computer users.

5



Tell Me / Show Me

Key Terms (continued)

• Client: a workstation or desktop computer including a

screen, keyboard, and mouse. Clients communicate directly

with human computer users.

• Server: a more powerful computer that accepts work

requests from clients, does the work, and sends results

back to the client.

Every time you request information from a Web page, your client

computer sends the request to a database on the server. The

server retrieves the data from the database, converts it into useful

information and sends the information back to the client.

If you pursue a career in IT you will hear and use these terms

nearly every day!

6



Tell Me / Show Me

History of Computer

Systems:

1970s

The database software

resided in the mainframe

computer. Almost all of the

computer processing was

done on these large

mainframe computers.

Some of these computers

were larger than your

classroom!

1970s Mainframe

MAINFRAME Dumb Terminals

DATABASE

7



Tell Me / Show Me

1970s (continued)

Smaller computers, or

“dumb terminals,” were used

to access the large

mainframe and execute

commands. The terminals

depended on the mainframe

and displayed the results

only after the processing

was completed in the

mainframe. They were not

capable of much processing

on their own.

1970s Mainframe

Dumb TerminalsMAINFRAME

DATABASE

8



Tell Me / Show Me

1980s

As personal computers

(PCs) became faster

and widely available,

processing moved from

the mainframes to the

clients.

Because the PCs had

their own software and

were capable of doing

some processing on

their own, they came to

be known as “smart

clients” or

“workstations.”

1980s Personal Computer

Server Computer:

Software

Smart Clients:

GUI Interface and Software

DATABASE

DATABASE

9



Tell Me / Show Me

1980s (continued)

Having the processing

power within the client

machine ushered in a

wave of graphical user

interface (GUI)

applications. Many of

the common

applications today

(Word, Excel,

PowerPoint) were born

during this era.

1980s Personal Computer

Server Computer:

Software

Smart Clients:

GUI Interface and Software

DATABASE

DATABASE

10



Tell Me / Show Me

The Problem of Isolated,

Nonintegrated Systems

Having multiple applications

on multiple client

workstations created new

problems. In this example,

different software on

different systems requires

integration. This is usually

troublesome and

expensive. If an upgrade is

made to a software

application, each and every

server plus each and every

client must be upgraded.

Problems: Different Software

Districts Statewide

Systems

National

Financial

DATABASE DATABASE DATABASE

11



Tell Me / Show Me

The Problem of Isolated,

Nonintegrated Systems

(continued)

Think of a school district

updating school grades on one

system and attendance on

another. When a student

graduates, all this information

needs to be brought together.

Without an integrated system,

this can be a painful process.

Especially if there are

thousands of students who

attend thousands of days of

school! Who will pull all that

data together? How?

Problems: Different Software

Districts Statewide

Systems

National

Financial

DATABASE DATABASE DATABASE

12



Tell Me / Show Me

1990s and Beyond

Oracle’s strategy is to

use the Internet and fast

processing servers to

meet the needs of

organizations in storing

data and producing

information.

1990s and Beyond

DATABASE

Database Server:

Software

Application Server:

SoftwareThin Clients:

GUI Interface,

Browser

13



Tell Me / Show Me

1990s and Beyond

(continued)

The software that

manages the data is on

the database server. It

performs processing for

storage and retrieval.

Applications for business

operations sit on the

application server. It

performs processing for

document creation,

developing, interacting or

manipulating the data.

1990s and Beyond

DATABASE

Database Server:

Software

Application Server:


GUI Interface,

Browser

14



Tell Me / Show Me

1990s and Beyond (continued)

Clients can have

applications of their

own, but the essential

business applications

are accessed from

the clients using an

Internet browser.

1990s and Beyond

DATABASE

Database Server:

Software

Application Server:


GUI Interface,

Browser

15



Tell Me / Show Me

Grid Computing: A New Model

In the grid-computing model, all

of an organization’s computers in

different locations can be utilized

just like a pool of computing

resources. Grid computing builds

a software infrastructure that can

run on a large number of

networked servers. A user makes

a request for information or

computation from his/her

workstation and that request is

processed somewhere in the

grid, in the most efficient way

possible.

DATABASE

NEWS

SPORTS

ENTERTAINMENT

HOROSCOPES

PICTURES

MOVIES

CHAT ROOMS

GAMES

DATABASE powers the Web

WEB USERS

16



Tell Me / Show Me

Grid Computing: A

New Model (continued)

Grid computing treats

computing as a utility, like

the electric company. You

don’t know where the

generator is or how the

electric grid is wired. You

just ask for electricity and

you get it. Grid Computing

improves performance and

reliability for Oracle’s

system structures using

database servers,

application servers, and

client browsers.

DATABASE

NEWS

SPORTS

ENTERTAINMENT

HOROSCOPES

PICTURES

MOVIES

CHAT ROOMS

GAMES

DATABASE powers the Web

WEB USERS

17



Tell Me/ Show Me

Business Terminology

• Finance: refers to businesses that deal primarily with

money

• Logistics: can be defined as the planning, execution,

and control of the movement and placement of people

and/or goods

• Commerce: involves transactions (sales and

purchases) having the objective of supplying goods

and services

• Procurement: refers to all of the processes involved in

requesting, ordering, auditing and paying for goods

and services

• Distribution: commercial activity of storing and

transporting goods from sellers to buyers

18



Tell Me / Show Me

Terminology


Application

Client

Grid computing

Hardware

Infrastructure

Operating system

Server

Software

Finance

Logistics

Commerce

Procurement

Distribution

19



Summary



• Relate major transformations enabled by changes in

computing to day-to-day activities

• Define and give an example of these terms: hardware,

operating system, software

• Identify examples of e-businesses that use database

software and explain how it is essential to their success

• Explain the overall mission of the Oracle Corporation

20



Summary

Practice Guide



Oracle Academy Database Design

Instructor Resource Guide

INSTRUCTOR NOTES

SECTION 1 – Introduction to the Oracle Academy Lesson Slide 1: Introduction to the Oracle Academy Lesson Preparation This lesson provides both an overview of the Oracle Academy and perspective for the remainder of the course. What to Watch For Help students be realistic about the kinds of jobs they will qualify for when first entering the job market. Connections Encourage students to discuss with their counselor, the counseling center, and their parents realistic goals for career planning. Encourage students to continue researching career opportunities and the requirements needed. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Tell students about your experience and reasons for teaching the Oracle Academy. Discuss the benefits you feel the Academy brings to the school and to the students. Share your enthusiasm! Share the fact that the Academy is a unique experience that's designed to help students along the road to success and put them ahead of the game. Slide 4: Tell Me / Show Me – What kind of career do you want? If students have difficulty getting started, ask them what kind of jobs they would like to work at. What kind of education do these jobs require? Would a college degree help them in this job? Slide 5: Tell Me / Show Me – Labor statistics report… Ask students to name jobs in the fields mentioned above. Answers include:

• Publishing: Online magazines need Web developers, editors, reporters, and editors.

• Trade: Foreign-exchange companies need programmers and database administrators.

Oracle Academy 1 Database Design Copyright © 2011, Oracle. All rights reserved.



• Business services: Financial-services companies need online traders and market analysts. Call centers need network administrators.

• Membership organizations: Users' groups need membership program managers and Web developers to manage their websites.

• Point out that even for “non technical” jobs such as reporters and editors, computer skills and familiarity with the Internet are often required.

Ask students: What is a presence on the WWW? Who already has a presence? Answer: When a company has a website, when business is conducted on the Internet. Examples: Ford Motor Company, Mitsubishi Corporation, Amazon, Sony Corporation. Slide 6: Tell Me / Show Me – Survey Jobs and salaries in the IT field Normal salary excluding any special payments such as bonus or overtime Students should realize the growing demand for IT skills. However, they should also recognize that most jobs in IT require not only a college education but also some sort of technical certification. (Explain the chart: starting salary = x and average base salary = y). Slide 7: Tell Me / Show Me - Required education level… Students should be made aware of the growing demand for IT skills and the education required to meet those opportunities. In addition to postsecondary education, technical certifications may also be advantageous. Students will have an opportunity to get started on their certifications at the end of the Database Programming course with the Intro to Oracle SQL Certification exam. Slide 8: Tell Me / Show Me – Introducing The Oracle Academy The Oracle Academy is designed to educate secondary/high school students (ages 16 to 19) on the fundamentals of Internet and database technology and provide them with the necessary skills to pursue academic and professional opportunities. The Academy partners with secondary-education institutions to give students not only the technical skills that they need to survive in today's ever-advancing information age, but also the business and logic skills that they can carry with them for life. Slide 9: Tell Me / Show Me – For which careers does the Oracle Academy prepare you? HR is Human Resources (this may not be clear to your students). Database backups: this is a technique used by DBA's to ensure that if the database crashes, there will be a copy of the contents available. Slide 10: Tell Me / Show Me – For which careers does the Oracle Academy prepare you? (continued) No instructor notes for this slide



Instructor Resource Guide Slide 11: Tell Me / Show Me – For which careers does the Oracle Academy prepare you? (continued) In different companies these job titles may be different, but the roles still exist. These salaries are estimated and based on the U.S. job market. Let students know that they will be doing their own research on data like this as part of the program. Slide 12: Tell Me / Show Me – Database Design and Programming with SQL No instructor notes for this slide Slide 13: Tell Me / Show Me – Database Design and Programming with SQL (continued) No instructor notes for this slide Slide 14: Tell Me / Show Me – Database Programming with PL/SQL No instructor notes for this slide Slide 15: Tell Me / Show Me – Oracle Certification No instructor notes for this slide Slide 16: Tell Me / Show Me – Oracle offers educational initiatives…Think.com No instructor notes for this slide Slide 17: Tell Me / Show Me – Oracle offers educational initiatives… Thinkquest No instructor notes for this slide Slide 18: Tell Me / Show Me – Oracle offers educational initiatives… OAI No instructor notes for this slide Slide 19: Tell Me / Show Me – Oracle offers educational initiatives… WDP No instructor notes for this slide Slide 20: Summary No instructor notes for this slide Slide 22: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 1 - Data vs. Information Lesson Slide 1: Data vs. Information No instructor notes for this slide Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? All kinds of information No instructor notes for this slide Slide 4: Why Learn It? If you work in the information-technology industry… No instructor notes for this slide Slide 5: Tell Me / Show Me – Data vs. Information Data: Raw material, from which you can draw conclusions Information: Knowledge, intelligence, a particular piece of data with a special meaning or function More examples to illustrate the difference between data and information: Data: telephone directory (names, addresses, and phone numbers). Information: names and phone numbers of florists in your neighborhood - a useful selection from the data. Data: gathered during a government population census. Information: totals of people in the country grouped by age, occupation, which state or district they live in – useful summary calculations from the data. Slide 6: Tell Me / Show Me – Data vs. Information (continued) Use your background in education to explain how a school or educational institution uses a database to store information. The graphical user interface (GUI) is the screen that you see when you look at any computer application. Students may not be familiar with this term. Slide 7: Tell Me / Show Me – Data vs. Information (continued) No instructor notes for this slide Slide 8: Tell Me / Show Me – What is a database? Database: A centralized and structured set of data stored on a computer system Slide 9: Tell Me / Show Me – Documents, Pictures, Video, and Sound Think of the different kinds of data that a school system stores: student grades, student pictures, video recordings of school events, etc.



Instructor Resource Guide Slide 10: Tell Me / Show Me – Question: What does a database have to do with… No instructor notes for this slide Slide 11: Tell Me / Show Me – If you had one of the jobs listed below… Ask students to think about how an auto mechanic, taxi driver, or landscape gardener might use a database? Possible answers include:

• Mechanic: looking up service records on a car; pricing a part carried by a supplier.

• Taxi driver: searching a website such as Yahoo to get driving directions. • Landscape gardener: looking up information on plants or pesticides.

It is useful to understand the data requirements of the business you work in. Slide 12: Tell Me / Show Me – Have you ever returned an item to a store… Lead discussion with students on this topic: Ask students why they think this is possible? Currently in some department stores, you can return items without receipts if you wrote a check or charged it on a credit card. The clerk simply types in your checking-account or credit-card number and up pops a list of every item you purchased using that payment type. That’s an example of getting information from a database! Another example: Have you ever lost your copy of your class grades and had to ask the school for another copy? What questions did you have to answer, and how did the school use your answers to provide the copy? Slide 13: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 14: Summary – In this lesson, you have learned how to: No instructor notes for this slide Slide 15: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 1 - History of the Database Lesson Slide 1: History of the Database Lesson Preparation Resources for the history of the database timeline:

• http://math.hws.edu • http://wwwdb.web.cern.ch/wwwdb • http://www.falasha-recordings.co.uk • http://news.bbc.co.uk

What to Watch For No further teaching information for this page. Connections Make sure students understand that the use and expansion of Internet technology is at different stages throughout the world. Encourage students to read and explore advances in technology in other countries. Help students think globally. Reinforce Oracle's commitment to education and the reasons why the company feels that educating young adults is an important goal for society. Slide 2: What Will I Learn? Do not spend a long time on the first part of this lesson. The important point is that students understand that database technology and its uses are not static. Today’s databases are very different from those of 20 years ago. Future databases will be different again. Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – History of the Database Timeline Non-relational databases, including hierarchical databases such as IBM’s IMS, preceded relational databases. And some of them are still in use today. This history focuses only on relational databases, which are easily the most widely used today because of their flexibility and relative ease of use. Slide 5: Tell Me / Show Me – History of the Database Timeline (continued) No instructor notes for this slide Slide 6: Tell Me / Show Me – Question: What does a database… No instructor notes for this slide



Instructor Resource Guide Slide 7: Tell Me / Show Me – Database Development Process Begins With… No instructor notes for this slide Slide 8: Tell Me / Show Me – Database Development Process Share with students that this is exactly what they will learn in the Data Modeling course. They will be able to transform business requirements into data models (ERDs). Slide 9: Tell Me / Show Me – Database Development Process (continued) Datatype: to the format and definition of the data in each column Primary key (PK) is the unique identifier for each row of data Foreign key (FK) links data from one table to another by referring to a column in that other table Nulls: indicate if the columns must have a value (mandatory) Unique: indicates if the value in the column is unique within the table Table instance chart: A relational database design used to map the information in the entity relationship model Students will also learn how to do this later in this course. Slide 10: Tell Me / Show Me – Database Development Process (continued) Ask students what they think this means? Answer: In SQL, they’ll learn how to make the actual database. Right now, it’s all about understanding what is needed using smart planning and careful design. Slide 11: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 12: Summary – In this lesson, you have learned how to: No instructor notes for this slide Slide 13: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 1 - Major Transformations in Computing Lesson Slide 1: Major Transformations in Computing Lesson Preparation No further instructions for lesson preparation. What to Watch For Continue to encourage students to think globally. Encourage them to find other Internet sites of business around the world. Connections Ask students what they predict shopping habits will be like in the next 20 years. Will we shop online for all our goods and services? How will today's local small businesses compete? Are there businesses that won't ever need a database or visibility on the Internet? Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me –Key terms Ask students for specific examples of hardware, operating systems, and software. Answers will vary, but possible responses include:

• Hardware - workstation (desktop) computer, mainframe, monitor, keyboard • Operating systems - Windows XP, Linux, Mac OS X • Applications - games, MSOffice, Macromedia Flash, Adobe Photoshop, etc.

Slide 5: Tell Me / Show Me – Key terms (continued) Two more terms you may want to mention: in a 2-tier system, clients communicate directly with servers. In a 3-tier system, clients communicate with a third computer in the middle, which forwards the requests to the servers. The middle-tier computer is often called an application server or web server. Slide 6: Tell Me / Show Me – History of Computer Systems: 1970s Point out a disadvantage of this system: if the mainframe computer fails, no work can be done. Slide 7: Tell Me / Show Me –1970s (continued) No instructor notes for this slide



Instructor Resource Guide Slide 8: Tell Me / Show Me – 1980s No instructor notes for this slide Slide 9: Tell Me / Show Me – 1980s (continued) Contrast a GUI application (like anything on the Internet) with a non-GUI application that is just all text. Your students may not even be old enough to remember anything like it. However, they will understand that displaying graphics requires more memory and processor speed (they know this from their video games). The earliest PCs were not equipped with enough “muscle” for GUI interfaces. Slide 10: Tell Me / Show Me - The Problem of Isolated, Nonintegrated Systems This is a problem that a lot of companies face if they have disparate systems that evolved separately. Slide 11: Tell Me / Show Me – The Problem of Isolated, Nonintegrated Systems (continued) No instructor notes for this slide Slide 12: Tell Me / Show Me – 1990s No instructor notes for this slide Slide 13: Tell Me / Show Me – 1990s (continued) An example would be a program that manages human-resource data or school records. Ideally, client users only need a browser to use the application, which then accesses the database. Advances in processing power allow this type of transaction to take place quickly and efficiently. This allows changes or upgrades to be made on the servers once instead of having to change and maintain many software applications on many client machines. The slide shows only one database server and one application server, but there could be several of these. Slide 14: Tell Me / Show Me – 1990s (continued) No instructor notes for this slide Slide 15: Tell Me / Show Me – Grid Computing: The New Model No instructor notes for this slide Slide 16: Tell Me / Show Me – Grid Computing: The New Model (continued) No instructor notes for this slide



Instructor Resource Guide Slide 17: Tell Me / Show Me – View the video clip… See if students recognize any of the sites. Discuss what kind of transactions can be conducted on the Internet (for example: buy books/cds on amazon.com). Point out that behind the scenes, computers are working to display the information on the web. Use the example of amazon.com: if you have previously purchased something from them, they “know” you the next time you visit the site. They make recommendations based on products you bought before. Where is all this information stored? (Answer: in a database) Most students may not be familiar with how businesses work. The terms finance, logistics, commerce, procurement, and distribution may be difficult to understand in context. Relate these terms to businesses that most will understand such as an online bookstore, the local grocery store or a clothing store. Finance: refers to businesses that deal primarily with money. Examples: banks, brokerage firms, real-estate money lenders Logistics: can be defined as the planning, execution, and control of the movement and placement of people and/or goods, and of the supporting activities related to such movement and placement within a system organized to achieve specific objectives. Examples: airlines, freight companies, food establishments Commerce: involves transactions (sales and purchases) having the objective of supplying commodities (goods and services). Examples: retail stores, online catalog sites Procurement: refers to all of the processes involved in requesting, ordering, auditing, and paying for goods and services. Procurement software tracks all the possible codes, inventories, addresses, etc. for producing, shipping, or ordering a specific product. Examples: office-supplies ordering system, ordering of uniforms for the military Distribution: the commercial activity of transporting and selling goods from a producer to a consumer. Examples: shippers (UPS, Fedex, DHL) Note: There are overlaps between these terms. Example: Logistics may involve using procurement and distribution software. Commerce may involve financial applications. Slide 18: Tell Me / Show Me – Business terminology Finance: refers to businesses that deal primarily with money Logistics: can be defined as the planning, execution, and control of the movement and placement of people and/or goods, and of the supporting activities related to such movement and placement within a system organized to achieve specific objectives. Commerce: involves transactions (sales and purchases) having the objective of supplying commodities (goods and services). Procurement: refers to all of the processes involved in requesting, ordering, auditing, and paying for goods and services. Distribution: the commercial activity of transporting and selling goods from a producer to a consumer.



Instructor Resource Guide Slide 19: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 20: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 21: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 1 – Introduction to the Oracle Academy Lesson Try It / Solve It 1. This activity aims to develop your skills for locating, evaluating, and interpreting IT

career information. Use Internet resources provided by your teacher to identify a job in the IT career field that interests you. Then, answer the following questions about that career:

a. What are the typical tasks involved in this job? b. What kind of social, problem-solving or technical skills are required? c. What are the physical demands of the job? d. What kind of training/education is required for the job? e. Where are current job openings? f. What other jobs could be a starting job that leads to this career? g. How many different kinds of businesses use these job skills? h. What is the salary range?

Solution: Using Internet resources, ask students to identify a job in the IT career field that interests them and answer the questions about that career. You can use the resources provided below, or find more with your preferred Internet search engine using the keywords: "jobs + asia sites", "jobs + europe sites"

Jobs in the United States • US Department of Labor Career Guide to Industries: Excellent resource for all

types of job working conditions, occupations, predicted growth/decline • Portal to a list of IT companies.: Many of the sites have a "career" link that

provides information about the type of jobs each offers • Alphabetical list of jobs such as "database developer" with specific company

job descriptions • Job seekers and employers • http://www.google.com - keyword "Information Technology careers" Jobs in Eastern Europe, Belarus, Romania, Russia, Czech Republic and Hungary • Lists of job search sites • http://www.ngonet.org/jobs • http://www.job-hunt.org/europ.shtml • http://www.monster.co.uk/




Jobs in Asia – Pacific • http://www.escapeartist.com/as/pac.htm

2. Describe how one of the Academy courses and a certification exam could help you

with your future job opportunities.

Solution: Answers will vary.



Instructor Resource Guide SECTION 1 - Data vs. Information Lesson Vocabulary Directions: Identify the vocabulary word for each definition below.

Database A collection of data arranged for ease and speed of search and retrieval.

Graphic User Interface (GUI) An interface for issuing commands to a computer utilizing a pointing device, such as a mouse, that manipulates and activates graphical images on a monitor.

Data Raw material, from which you can draw conclusions

Information Knowledge, intelligence, a particular piece of data with a special meaning or function

Try It / Solve It 1. List specific data that the school collects about each student. What information could

be gathered using all the student data?

Possible responses for data include: name, address, phone number, names of parents or guardian, age, sex, nationality, parking place, discipline history, academic history or attendance history, grades, test scores, ethnic background. Possible responses for information include: The ethnic groups represented in the school, what percentage of students drive a car to school, how many students have grade-point averages greater than 3.0 (information), performance of different ethnic groups on standardized tests, diversity of the school population, possible locations for new schools, etc.



Instructor Resource Guide 2. Review an online database such as:

http://www.archives.gov http://www.ellisislandimmigrants.org http://newdeal.feri.org/index.htm http://www.pro.gov.uk/ http://nationalarchives.nic.in/

a. Write examples of data and information related to the site you choose. b. State why you believe data collections of this type could be important.

Possible answers: to keep a historical record of immigration into a country, laws passed, etc.

3. Choose a website, find 10 data items on the site and list 5 pieces of information that

could be gleamed from the data.

Solution: Have students share their data in a game with the students competing to see who has the most unique data and information. One student reads his/her list of data aloud. If someone else in class has that piece of data or information, no one gets a point for it. If only that student has the data/info on his/her list, that student gets a point. Go through all data/info items and have students report their points. Reward the highest score!

4. Give examples of how data becomes information for these two industries: film/movie,

hospital/healthcare.

Some answers may include: Film data: cast, directors, producers, awards, box office figures Information: type of movies that win the most awards, actors who consistently appear in the top-grossing movies, studios that produce the most profitable movies Hospital data: patient names, diagnosis, medication, tests, etc.



Instructor Resource Guide 5. Name all the different kinds of information that appear on the Lunch Room Data

Report.

Date Student Sales

Faculty/Staff Sales

Hamburger/Taco Bar

Pizza Bar Soup/Salad Bar

12/02/03 497 23 335 122 63 12/03/03 440 19 285 126 48 12/04/03 447 30 301 126 50 12/05/03 442 27 325 107 37 12/06/03 330 12 229 83 30

a. What does this report mean?

It is about food items purchased in a lunch room, most likely in a school. b. What data was collected?

The table shows the count of types of food items (hamburger/taco, pizza, soup/salad) purchased per day, broken out by faculty sales and student sales. It seems that the data is collected weekly.

c. What information does this table provide?

The table gives us information about which items are the most popular. d. How do you think these data are used?

It could be used to plan inventory for food and to assign duties in the kitchen and at the serving counter.

e. Generate at least two conclusions based on the data provided.

Hamburgers and tacos are the most popular food; soup and salad are the least popular.

f. Generate at least two questions that you would ask about the data provided.

Do students and teachers prefer the same food? How do the total counts for students and teachers break down in terms of type of food purchased?



Instructor Resource Guide SECTION 1 - History of the Database Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Table instance chart A relational database design used to map the

information in the entity relationship model

Primary key (PK) the unique identifier for each row of data

Foreign key (FK) Links data from one table to another by referring to a column in the other table

Nulls Columns that must have a value assigned to them

Unique Indicates if the value in the column is unique within the table

Datatype Refers to the format and definition of the data in each column

Try It / Solve It 1. Complete the diagram by listing in the boxes, the important aspects of the database

evolution. Refer to answer for question 5

2. True or False: The Personal Digital Assistant (PDA) was an important historical

contribution in database development and design True 3. Name two important historical contributions in database development and design.

Answers will vary



Instructor Resource Guide 4. If Building the database is the third major task in the database development process

then what are the first two major tasks? Data Modeling, Database Design 5. (Optional) List at least three timeline events in the evolution of the database.

1960s: Computers become cost effective for private companies along with increased storage capability. 1970-72: E.F. Codd proposes the relational model for databases, disconnecting the logical organization from the physical storage. 1976: P. Chen proposes the entity relationship model (ERM) for database design. Early 1980s: The first commercially-available relational database systems start to appear at the beginning of the 1980s with Oracle Version 2. Mid-1980s: SQL (structured query language) becomes "intergalactic standard." Early 1990s: An industry shakeout begins with fewer surviving companies. Oracle survives. Mid-1990s: Kaboom! The usable Internet/World Wide Web (WWW) appears. A mad scramble ensues to allow remote access to computer systems with legacy data. Late 1990s: The large investment in Internet companies helps create a tools market boom for Web/Internet/DB connectors. Early 21st century: Solid growth of DB applications continues. Examples: commercial websites (yahoo.com, amazon.com), government systems (Bureau of Citizenship and Immigration Services, Bureau of the Census), art museums, hospitals, schools, etc.

6. (Optional) To most of us, the Internet has become an essential element in the way we

communicate, the way we do business, and the way we learn. Surprisingly, few people really know the history and the people that have contributed to its phenomenal growth.

In this activity, you and your classmates will construct a wall mural timeline of the major historical events in Internet history. Using Internet resources, your group will be assigned one topic from the research list. Your group's task is to gather information to add to the classroom timeline:

Find four events that describe your topic. Each event must have a person, place, and/or thing associated with it. Add your group's information to the timeline.

Research List:

• Historical thinkers: people without whose inventions computers and communication as we know it today could not be possible

• Enablers: universities, government agencies, and businesses that contributed to the idea of the Internet and birth of the Internet

• Communicators: people who developed computer languages, computer networks, and the technology to be able to talk computer to computer




• Innovators: people and businesses that enabled the average person to be able to use a computer and communicate on the Internet

• Movers and shakers: people and companies that transformed the Internet into a virtual mall of information and services

Solution: In this lesson, students will use the Internet to research the people and businesses that contributed to the development of the Internet. Internet search keywords "internet timeline" or "Hobbe's Internet Timeline." Using adding-machine-tape paper or poster paper cut into strips, create a 10-foot mural for the classroom. Divide the paper into a timeline as follows: allow about 1/4 of the length from 1800 to 1970 and the remaining 3/4 from 1970 to present. Assign topics to groups. Each group should find a minimum of four events. Each group must identify a person, a place, and a thing associated with their topic.

The topics to be included are:

• Historical thinkers: people without whose inventions computers and

communication as we know it today could not be possible (Samuel Morse, Alexander Graham Bell, Vannevar Bush)

• Enablers: universities, government agencies, and businesses that contributed to the idea of the Internet and birth of the Internet (ARPANET, NSF, CERN, Rand Corp.)

• Communicators: people who developed computer languages, computer networks, and the technology to be able to talk computer to computer (Ray Tomlinson, Bob Metcalf, Vinton Cerf, Larry Wall)

• Innovators: people and business that enabled the average person to be able to use a computer and communicate on the Internet (Microsoft, Apple, AOL, Netscape, Yahoo)

• Movers and shakers: people and companies that transformed the Internet into a virtual mall of information and services (Oracle, Amazon.com, EBay, MSN)



Instructor Resource Guide SECTION 1 - Major Transformations in Computing Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Infrastructure The basic framework or features of a system Grid computing A global effort to develop an environment in which

individual users can access computers, databases, and experimental facilities simply and transparently, without having to consider where those facilities are located

Software The programs, routines, and symbolic languages that control the functioning of the hardware and direct its operation.

Hardware A computer and the associated physical equipment directly involved in the performance of data-processing or communications functions.

Operating System Software designed to control the hardware of a specific data-processing system in order to allow users and application programs to make use of it.

Application A software program which carries out specific tasks on behalf of computer users

Client A workstation or desktop computer including a screen, keyboard, and mouse; communicates directly with the user

Server A more powerful computer which accepts work requests from clients, does the work, and sends results back to the client

Try It / Solve It 1. Provide a definition and an example of each of these:

a. Hardware: the physical components of a computer. Mouse, keyboard, screen, memory, stick drive are some examples

b. Operating system: a software program which directly controls and manages the hardware. Sun Solaris, Microsoft Windows, Red Hat Linux are examples

c. Software: programs (sets of instructions) which tell the hardware what to do. Microsoft Word, Palm Desktop, Mozilla Browser are examples



Instructor Resource Guide 2. How has the major transformation of cell phones impacted day-to-day activities of a

service repair company – what can the service repair person do today that they could not do before this transformation?

Answers will vary. Students should be able to point out that cell phones now enable a service repair person to call before arriving, call to inform the customer if they are going to be late, call to order parts before returning to the depot, etc.

3. List three e-businesses that use database software and describe how the database

software is being used.

Answers will vary. Check for students understanding that database software, for any business, can store and display information stored in the database.

4. Write down the steps of a simple credit-card transaction. How many places does the

information go, and what happens if the transaction is not complete at any one of the steps? What role does a database play in this process?

Note: The students may not have all these steps. That is all right as long as they have a general idea of how a database plays a big role in the process.

Solution: Steps in a simple credit-card transaction: a. Customer presents credit card. b. Store runs credit card through the system to get customer information: card

number, name. c. Store takes the customer information and creates an entry for the purchase, using

information from its database (item number, price, discount, etc.). d. Store information, details and amount of purchase is sent to the credit card

company for approval. e. Credit card company uses customer information from its own database to check

credit limit, run identity-theft checks, etc. f. Both databases (store and credit-card company) are updated. g. If at any time the transaction is not completed (customer changes mind and stops

transaction, or transaction puts customer over the credit limit), the purchase information is not entered in either database.

h. If identity theft is suspected, credit-card company will create a record in its database and contact credit-card owner. Sale may not be completed if the credit-card company blocks the purchase.



Drawing Conventions for Readability

2



What Will I Learn?

Objectives


• Apply the Oracle drawing conventions to a datamodel

diagram

• Identify high volume entities in a datamodel diagram and

explain their significance to the business

• Redraw a given datamodel diagram to increase clarity

and readability

• Recognize the usefulness of dividing a complex ERD into

a number of functional sub-diagrams

3



Why Learn It?

Purpose

What if all shoemakers made up their

own sizes?

What if every architect used a different

system to draw plans for a building?

Following the same conventions makes it

easier to work as part of a team.

Watch the video clip. How easy is it to

understand the ERD at the end?

sdm_s11_l02_a01

4



Tell Me / Show Me

Large ERD Drawing

Conventions

As the ERD gets bigger and more

complicated, it becomes more

challenging to lay it out in a clear

and readable format.sdm_s11_l02_a02

5



Tell Me / Show Me

Large ERD

Drawing

Conventions

(continued)

Following the

conventions of

“crows flying

south and east”

places the high

volume entities

on the upper left

portion of the

ERD.

JOB ASSIGNMENT PARTNER

EVENT CLIENT

PRIVATE SPACE PUBLIC SPACE

6



Tell Me / Show Me

Large ERD

Drawing

Conventions

(continued)

High volume

entities are

those that would

have the most

number of

instances,

compared to

other entities.

JOB ASSIGNMENT PARTNER

EVENT CLIENT


7



Tell Me / Show Me

Large ERD Drawing Conventions

(continued)

Following the conventions of “crows

flying north and west” places the

high volume entities on the lower

right portion of the ERD.


EVENTCLIENT

PARTNER JOB ASSIGNMENT

8



Tell Me / Show Me

Large ERD Drawing

Conventions

(continued)

High volume entities

are often the “central”

or more important

entities in an ERD.

They will have the

highest number of

relationships to other

entities, and most of

the business functions

will affect the data

stored in this entity.


EVENTCLIENT

PARTNER JOB ASSIGNMENT

9



Tell Me / Show Me

Clarity Is Key

Often you will

have a mix,

depending on

the amount of

space you have

and your own

preference.

Clarity and

readability are

the main criteria.

CLIENT

EVENT JOB

ASSIGNMENTPARTNER


10



Tell Me / Show Me

Clarity is Key (continued)

The high volume entities are

not always the most

important.

Which of these entities

would have the highest

volume?

Which entity is the most

important?

Again, clarity and readability

are the main criteria.

ENROLLMENTCLASS

TEACHERSTUDENT

11



Space is Needed

Readability takes space and is subject to taste. The use of

white space helps clarify an ERD.

Tell Me / Show Me

A

B

C

D

E

F

A B

CE

D F

12



Use Sub -Diagrams

When you have a very

large diagram, it may

also help to break it up

into smaller diagrams of

functionally related

entities. You could use

the smaller sub-

diagrams when

presenting to different

groups within the

customer’s company.

This is what the project

manager would mainly

be interested in.

Tell Me / Show Me

JOB ASSIGNMENT

* status

# date

EVENT

# id

* cost

* name

* date

° description

EVENT

PLANNER

OTHER

PARTNER

# id

* first name

* last name

DJ

* specialty

MANAGER

o authorized expense limit

CLIENT

# number

* first name

* last name

* phone number

° email address

13



Sub-Diagram

Example

These entities are

what the event

manager would

be most

concerned with.

Tell Me / Show Me

EVENT

# id

* cost

* name

* date

o description

CLIENT

# number

* first name

* last name

* phone number

o email address

THEME

# code

* description

PRIVATE HOME

# id

* address

o comments

PUBLIC SPACE

# id

* address

* rental fee

o comments

14



Sub-Diagram Strategy

Often multiple

developers build the

applications that access

a single database. Each

application developer

could use a smaller

diagram that contains

the entities that he or

she will build screens,

forms, and reports for.

These are the entities

that one of greatest

interest to the DJ, or

someone building an

application for the DJ.

Tell Me / Show Me

PLAY LIST ITEM

o comments

TRACK LISTING

* track

CD

# number

* title

* producer

* year

EVENT

# id

* name

* date

* cost

o description

SONG

# id

* title

o duration

o artist

THEME

# code

* description

TYPE

# code

* description

15



Tell Me / Show Me

Terminology


High volume entity

White space

16




In this lesson you have learned to:

• Apply the Oracle drawing conventions to a datamodel

diagram

• Identify high volume entities in a datamodel diagram and

explain their significance to the business

• Redraw a given datamodel diagram to increase clarity

and readability

• Recognize the usefulness of dividing a complex ERD

into a number of functional sub-diagrams

Summary

17



Practice Guide



Summary

1

Generic Modeling


Generic Modeling

2

Generic Modeling


What Will I Learn?

Objectives


• Define generic modeling

• Evaluate and describe the advantages

and disadvantages of generic modeling

• Construct a generic version of a more

specific data model

3

Generic Modeling


Why Learn It?

Purpose

Generic models can reduce the number of

entities in a diagram and provide a lot of

flexibility in unstable situations, where the

business requirements change often.

A business that needs to frequently add

entities and/or attributes could benefit from

generic modeling. One example would be

a pawnshop that buys and sells different

types of items all the time. It would be

difficult to predict the number of item types

and the different attributes each type

would have.

sdm_s11_l03_a01

4

Generic Modeling


Tell Me / Show Me

Generic

Modeling

Generic

modeling looks

at the same

context from

another, more

distant

perspective.

From a distance,

many things look

the same.

MANUFACTURER

# name

ARTICLE TYPE

# name

ARTICLE

# id

* length

* material

° waistband type

° bodice cut

° hem circumference

° neck size

° sleeve length

MANUFACTURER

# name

SHIRT

* id

* length

* material

* neck size

* sleeve length

SKIRT

# id

* length

* material

* waistband type

* hem circum

DRESS

# id

* length

* material

* bodice style

PANTS

# id

* length

* material

° waistband type

produced

the

producer

produced classified

GENERIC MODEL

the

producer

5

Generic Modeling


Tell Me / Show Me

Choosing a Generic Model

Suppose you are to make a model for a

clothing store. The business typically sells

many different articles: shoes, shirts, dresses,

pants, and so on. For each type of clothing

article, there are different attributes. You can

model every type as an entity. Or you could

create a more generic model that uses one

entity, ARTICLE, with or without subtypes.

However, this model would be fine only if

there were no (or possibly very few) new

instances of ARTICLE TYPE during the life

cycle of the system.

6

Generic Modeling


Tell Me / Show Me

Recycling of Attributes

Another generic model

involves recycling

attributes.

Using this structure, here

are some examples of

instances of ARTICLE

TYPE:

the classification

for

classified

by

the producer

of

produced

by

ARTICLE TYPE

# name

* definition of Prop. 1



o definition of Prop. 4

…

MANUFACTURER

# name

VALUE

* value of Prop. 1

* value of Prop. 2

* value of Prop. 3

o value of Prop. 4

o value of Prop. 5

o value of Prop. 6

o value of Prop. 7

…

7

Generic Modeling


Tell Me / Show Me

Recycling of Attributes (continued)

Name Def. of

Prop. 1

Def. of Prop

2

Def. of

Prop 3

Def of

Prop 4

Def of

Prop 5

SHIRT id Length Material Neck Size Sleeve

Length

SKIRT Id Length Material Waistband

Type

Hem

Circum.

DRESS id Length Material Bodice

Style

PANT id Length Material Waistband

Type

You can also store information about the data types of each

property in the definition attributes (example: property 2 for all

articles (length) has a data type of number, property 4 of

DRESS (bodice style) is stored as text).

8

Generic Modeling


Tell Me / Show Me

Example

These would be the examples of corresponding instances of

ARTICLE.

the classification

for

classified

by

the producer

of

produced

by

ARTICLE TYPE

# name




o definition of Prop. 4

…

MANUFACTURER

# name

VALUE

* value of Prop. 1

* value of Prop. 2

* value of Prop. 3

o value of Prop. 4

o value of Prop. 5

o value of Prop. 6

o value of Prop. 7

…

9

Generic Modeling


Tell Me / Show Me

Generic Values

Using this method, you can add new types of articles fairly

easily, provided that the number of attributes does not exceed

the maximum that was originally defined.

ARTICLE

TYPE

Name

Def. of

Prop. 1

Def. of

Prop 2

Def. of

Prop 3

Def of

Prop 4

Def of

Prop 5

SHIRT DNM105 40 Denim 16 33

SKIRT LIN200 22 Linen Elastic 60

DRESS SHF119 60 Jersey Empire

PANT CHN407 33 Khaki Flat Front

10

Generic Modeling


Tell Me / Show Me

Attributes Modeled as

Property Instance

This model takes a third

approach. Every value for a

property of an ARTICLE is

stored separately. This model

gives a lot of freedom to define

new articles and properties

during the life cycle of the

system.

Using this structure, here are

some examples of instances of

each entity:ARTICLE PROPERTY VALUE

* value

ARTICLE

# id

PROPERTY

# number

MANUFACTURER

* name

ARTICLE TYPE

# name

the

producer

of

produced

by

the

classification

for

classified

by

the

owner

of

owned

by

the

holder

of

held

by

contained

in

the

container

for

11

Generic Modeling


Tell Me / Show Me

Name …

SKIRT

SHIRT

DRESS

PANT

ARTICLE TYPE

Article

Type Name

No. Desc. …

SHIRT 1 Length

SHIRT 2 Material

SHIRT 3 Neck size

SKIRT 1 Length

PROPERTY

Article Type

Name

Id …

SHIRT DNM105

SKIRT LIN200

DRESS SHF119

PANTS CHN407

ARTICLE

Article ID Article Type Name PROPERTY Number Value …

DNM105 SHIRT 1 40

DNM105 SHIRT 2 Denim

DNM105 SHIRT 3 16

LIN200 SKIRT 1 22

ARTICLE PROPERTY VALUE

Attributes Modeled as Property Instance (continued)

12

Generic Modeling


Tell Me / Show Me

Generic Model Benefits

The benefits of a generic model include:

(1) Flexible -- can prevent the need to

change data structures in the future

(2) Can reduce the number of entities

dramatically

Cost: Increased complexity in both the data

model and application programs

sdm_s11_l03_a02

13

Generic Modeling


Tell Me / Show Me

Terminology


Generic

Perspective

14

Generic Modeling




• Define generic modeling

• Evaluate and describe the advantages and

disadvantages of generic modeling

• Construct a generic version of a more specific data

model

Summary

15

Generic Modeling


Practice Guide

The link for the lesson practice guide can be found in

the course resources in Section 0.

Summary


Introduction to Relational Database

Concepts

2

Introduction to Relational Database Concepts


What Will I Learn?

Objectives


• Define a primary key

• Define a foreign key

• Define a column-integrity rule

• Identify row, column, primary key, unique key, and

foreign key given a diagram of a table containing these

elements

• Identify violations of data-integrity rules

3



Why Learn It?

Purpose

The conceptual data model will be transformed into a

relational database design. This means that our entities,

attributes, relationships, and unique identifiers will be

translated into objects in a relational database.

Compare this to a clothing designer that is taking their

design from paper and implementing it with fabric. The

designer needs to understand how to sew the designs just

like you will need to understand the structure of relational

database objects.

4



Tell Me / Show Me

Relational Database Illustrated

A relational database is a database that is seen by the user as a collection of two-dimensional tables.

The table below contains employee data.

Row

Column

EMPLOYEES (table name)

110HigginsShelley205

10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100

DEPARTMENT_IDLAST_NAMEFIRST_NAMEEMPLOYEE_ID

5



Tell Me / Show Me

Language to Access Data

Structured query language (SQL) allows us to access data

in relational databases in an efficient way. Instead of going

through each row to find the record for employee number

200, we use the following SQL statement:

SELECT last_name, department_id

FROM employees

WHERE employee_id = 200;

You can see the result of this statement on the next slide.

6



Tell Me / Show Me


SELECT last_name, department_id

FROM employees

WHERE employee_id = 200;

10Whalen

DEPARTMENT_IDLAST_NAME


10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100


SQL Query Illustrated

7



Tell Me / Show Me

Specific SQL Query

To find all the employees in department number 90, we

write a different SQL statement:

SELECT *

FROM employees

WHERE department_id = 90;

Again, you can see the result on the next slide.

8



Tell Me / Show Me



SELECT *

FROM employees

WHERE department_id = 90;

90De HaanLex102

90KochharNeena101

90KingSteven100

DEPARTMENT_IDLAST_NAMEFIRST_NAMEEMPLOYEE_ID ...

...

...

...


10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100


...

...

...

...

...

Specific SQL Query (continued)

9



Tell Me / Show Me

Primary Key

A primary key (PK)

is a column or set

of columns that

uniquely identifies

each row in a

table.

22-SEP-035.0075760105

10-MAR-9115,001.8555890103

15-JAN-8555,775.0089570105

100.1077956104

21-OCT-8912,0050.0075760104

DATE_OPENEDBALANCEACCT_NOBANK_NO

ACCOUNTS

Primary KeyEMPLOYEES

Primary Key


10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100


...

...

...

...

...

10



Tell Me / Show Me

Primary Key Rules

Each table should

have a primary key,

and a primary key

must be unique.

No part of the

primary key can be

null.22-SEP-035.0075760105

10-MAR-9115,001.8555890103

15-JAN-8555,775.0089570105

100.1077956104

21-OCT-8912,0050.0075760104


ACCOUNTS

Primary KeyEMPLOYEES

Primary Key


10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100


...

...

...

...

...

11



Tell Me / Show Me

Primary Key Candidates

A table can have more than one column or combination of

columns that could serve as the table’s primary key. Each of

these is called a "candidate" key.

Candidate Key Candidate Key

90386NEILLOUNGANI378

52CARLOSGOMEZ405

1101LAWRENCECHEN210

59877TYLERADAMS310

21215DANASMITH100

PAYROLL_IDFIRST_NAMELAST_NAMEMEMBER_ID

MEMBERS

12



Choose a Candidate Key

Select one candidate key to be the primary key for the table.

The other candidates become alternate keys (or unique

keys).

Tell Me / Show Me

MEMBERS

Primary Key Alternate or

Unique Key (UK)

90386NEILLOUNGANI378

52CARLOSGOMEZ405

1101LAWRENCECHEN210

59877TYLERADAMS310

21215DANASMITH100

PAYROLL_IDFIRST_NAMELAST_NAMEMEMBER_ID

13



Tell Me / Show Me

Foreign Key

A foreign key

(FK) is a column

or combination

of columns in

one table that

refers to a

primary key in

the same table

or another table.

Primary Key Foreign Key

Shipping50

Marketing20

Administration10

DEPARTMENT_NAMEDEPARTMENT_ID

DEPARTMENTS

refers to

Primary Key

EMPLOYEES


10WhalenJennifer200

90De HaanLex102

90KochharNeena101

90KingSteven100


14



Tell Me / Show Me

Foreign Key Rules

If a foreign key is part of a primary key, that FK cannot be

NULL.

LEARN TO SPEAK

SPANISH

Q3515

HARRY POTTERB247987

TALE OF TWO CITIESA815

LITTLE WOMENA6106

SHELF_NOSHELF_NOBOOK_NO

Q35

B24

A8

A6

SHELF_NO

SHELVES BOOKS

Primary Key Primary Key

Foreign

refers to

15



Tell Me / Show Me

Column Integrity

A column must

contain only

values consistent

with the defined

data format of the

column.

ACCOUNTS

DateDATE_OPENED

Not nullNumber (12,2)BALANCE

Not nullNumber (8)ACCT_NO

Not nullNumber (5)BANK_NO

OptionalityData TypeColumn Name

ACCOUNTS Table Definition

22-SEP-035.0075760105

10-MAR-9115,001.8555890103

15-JAN-8555,775.0089570105

100.1077956104

21-OCT-8912,0050.0075760104


16



Tell Me / Show Me

Summary of Data-Integrity Rules

Data-integrity rules (also known as constraints) define the

relationally correct state for a database. Data-integrity rules

ensure that users can perform only those operations that

leave the database in a correct, consistent state.

If the value in the balance column of

the ACCOUNTS table is below 1.00,

we must send a letter to the account

owner ( this will need extra

programming to enforce)

The data stored in a database must

comply with the rules of the business

User-Defined Integrity

The value in the balance column of

the ACCOUNTS table must be

numeric

A column must contain only values

consistent with the defined data format

of the column

Column Integrity

The value in the dept_no column of

the EMPLOYEES table must match a

value in the dept_no column in the

DEPARTMENTS table

A foreign key must match an existing

primary key value (or else be null)

Referential Integrity

The column emp_no in the

EMPLOYEES table cannot be null

A primary key must be unique, and no

part of the primary key can be null

Entity Integrity

EXAMPLEEXPLANATIONCONSTRAINT TYPE

17



Tell Me / Show Me

Terminology


Candidate key

Column

Foreign key

Primary key

Relational database

Row

Unique key

18



Summary



• Define a primary key

• Define a foreign key

• Define a column-integrity rule

• Identify row, column, primary key, unique key, and

foreign key given a diagram of a table containing

these elements

• Identify violations of data-integrity rules

19



Summary

Practice Guide




Basic Mapping: The Transformation

Process

2

Basic Mapping: The Transformation Process


What Will I Learn?

Objectives


• Distinguish entity relationship models from database

models

• Describe the terminology mapping between a

conceptual model and a relational database model

• Understand and apply the Oracle naming conventions

for tables and columns used in relational models

• Transform an entity into a table diagram

3



Why Learn It?

Purpose

When you design a house, you eventually would like to see

the house built. Even if you don’t do the actual construction,

you will need to understand the terms used by the builders in

order to help them take your design and make it a reality.

The initial database design can be used for further

discussion between designers, database administrators, and

application developers.

4



Tell Me / Show Me

Review of Relational Tables

A table is a simple structure in which data is organized and stored.

In the example below, the EMPLOYEES table is used to store

employees’ information.

Neil9038622NEILLOUNGANI378

Chaz5210CARLOSGOMEZ405

Larry110110LAWRENCECHEN210

Ty5987715TYLERADAMS310

Dana2121510DANASMITH100

NICKNAMEPAYROLL_IDDEPARTMENT_IDFIRST_NAMELAST_NAMEEMPLOYEE_ID

rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

5



Tell Me / Show Me

Review of Relational Tables (continued)

Tables have columns and rows. In the example, below, each row

describes an occurrence of an employee. Each column is used to

store a specific type of value, such as employee number, last

name, and first name.







rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

6



Tell Me / Show Me


The employee_id column is a primary key. Every employee has

a unique identification number in this table. The value in the

primary key column distinguishes each individual row.







rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

7



Tell Me / Show Me


The payroll_id is a unique key. This means that the system

does not allow two rows with the same payroll_id.







rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

8



Tell Me / Show Me


The foreign key column refers to a row in another table. In this

example, the department_id refers to a row in the

DEPARTMENTS table.







rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

9



Tell Me / Show Me


We know that Dana Smith works in department 10. If we wanted to

know more about Dana Smith’s department, we would look for the

row in the DEPARTMENTS table that has deptartment_id = 10.







rows

Primary Key

Column (PK)

Foreign Key

Column (FK)

Unique Key

Column (UK)

Table: EMPLOYEES

columns

10



Tell Me / Show Me

Transforming Conceptual To Physical

The conceptual model (ER diagram) is transformed into a physical

model. The physical implementation will be a relational database.

EMPLOYEE

# employee id

* first name

* last name

* payroll id

o nickname

DEPARTMENT

# department id

* department name

department_name*

department_id* pk

Column nameOptionalityKey type

DEPARTMENTS (DPT)

department_id*fk

nickname*

first_name*

last_name*

payroll_id*uk

employee_id*pk

Column nameOptionalityKey type

EMPLOYEES (EPE)

Conceptual Model (ERD)

Physical Implementation: Relational Database

Transformation

process

11



Tell Me / Show Me

Terminology Mapping

Changing from analysis (conceptual model) to design (physical

implementation) also means changing terminology:

• An entity becomes a table.

• An instance becomes a row.

• An attribute becomes a column.

• A primary unique identifier becomes

a primary key.

• A secondary unique identifier

becomes a unique key.

• A relationship is transformed

into a foreign-key column and

a foreign key constraint.

ANALYSIS

ER Diagram

DESIGN

Physical Design

Entity

Instance

Attribute

Primary UID

Secondary UID

Relationship

Table

Row

Column

Primary Key

Unique Key

Foreign Key

12



Tell Me / Show Me

Table Diagram

Notations

The first row of the table

diagram contains the

table name and the short

name.

The Key Type column

should contain values of

“pk” for the primary key,

“uk” for the unique key,

and “fk” for the foreign-

key column. It will be

blank if the column is not

a part of any key.

Column NameOptionality (“*”, “o”) Key Type (pk, uk, fk)

TABLE NAME (short name)

13



Tell Me / Show Me

Table Diagram

Notations (continued)

The Optionality column

must contain “*” if the

column is mandatory and

“o” if it is optional. This is

similar to the entity

diagram.

The third column is for

the column name.

Column NameOptionality (“*”, “o”) Key Type (pk, uk, fk)

TABLE NAME (short name)

14



Tell Me / Show Me

Naming Conventions

for Tables and

Columns

The table name is the

plural of the entity

name.

Example: STUDENT

becomes STUDENTS dob*

p_code*

state*

city*

str_addr*

last_name*

first_name*

id*pk

Column NameOptionalityKey TypeSTUDENT

# id

* first name

* last name

* street address

* city

* state

* postal code

* date of birth

STUDENTS

15



Tell Me / Show Me

Naming Conventions

for Tables and

Columns (continued)

• Column names are

identical to the

attribute names

except that special

characters and

spaces are replaced

with underscores.

Column names often

use more

abbreviations than

attribute names.

• Example: first name

becomes first_name,

or fname

dob*

p_code*

state*

city*

str_addr*

last_name*

first_name*

id*pk

Column NameOptionalityKey TypeSTUDENT

# id

* first name

* last name

* street address

* city

* state

* postal code

* date of birth

STUDENTS

16



Tell Me / Show Me

Table Short Names

A unique short name for every table is useful in the naming of

foreign-key columns. One possible way to make these short names is

based on the following rules:

For entity names of more than one word, take the:

• First character of the first word

• First character of the second word

• Last character of the last word

Example: JOB ASSIGNMENT gets a short name of JAT

comments*

address*

id*pk

Column NameOptionalityKey TypePRIVATE HOME

# id

* address

o comments

PRIVATE HOMES (PHE)

17



Tell Me / Show Me

Table Short Names (continued)

For entity names of one word but more than one syllable, take the:

• First character of the first syllable

• First character of the second syllable

• Last character of the last syllable

Example: EMPLOYEE gets a short name of EPE and CLIENT gets a

short name of CET

email_addro

phone_num*

last_name*

first_name*

client_num*pk

Column NameOptionalityKey Type

CLIENTS (CET)

CLIENT

# number

* first name

* last name

* phone number

o email address

18



Tell Me / Show Me

Table Short Names (continued)

For entity names of one syllable but more than one character:

• First character

• Second character

• Last character

Example: FLIGHT gets a short name of FLT

description*

code*pk

Column NameOptionalityKey TypeTHEME

# code

* description

THEMES (THE)

19



Tell Me / Show Me

Naming Restrictions with Oracle

Table and column names:

• Must start with a letter

• Can contain up to 30 alphanumeric characters

• Cannot contain spaces or special characters such as “!,”

but “$,” “#,” and “_“ are permitted.

Table names must be unique within one user account in the

Oracle database.

Column names must be unique within a table.

20



Tell Me / Show Me

Naming Restrictions with Oracle (continued)

Some words have a special meaning in the Oracle database and

in the SQL programming language. These are called “reserved”

words. It is best to avoid using these as names for your tables and

columns. Some common examples of Oracle reserved words are:

• TABLE

• NUMBER

• SEQUENCE

• ORDER

• VALUES

• LEVEL

• TYPE

A complete list can be found on Technet. (otn.oracle.com)

21



Tell Me / Show Me

Terminology


Transform

Map

Reserved word

22



Summary



• Distinguish entity relationship models from database

models

• Describe the terminology mapping between a conceptual

model and a relational database model

• Understand and apply the Oracle naming conventions for

tables and columns used in relational models

• Transform an entity into a table diagram

23



Summary

Practice Guide




Relationship Mapping

2



What Will I Learn?

Objectives


• Apply the rule of relationship mapping to correctly

transform 1:M and barred relationships


transform M:M relationships

• Transform 1:1 relationships


transform relationships in an arc

3



Why Learn It?

Purpose

What if you were building a house for someone? You buy all

the materials – wood, paint, doors, windows, nails, screws,

etc. – but you do not know how to put all the pieces together.

You don’t know how many rooms there should be, where the

windows should be placed, how the doors should be oriented,

or what color each room should be painted. You could build a

house in such a manner, but if you do not have a plan or

blueprint identifying how the pieces of the house go together,

the final product may not be the house that the customer has

in mind.

4



Why Learn It?

Purpose (continued)

Relationships are mapped to foreign keys that allow tables to

reference each other. Foreign keys enable users to access

related information from other tables. If we don’t map

relationships, we just have a lot of standalone tables containing

information that can’t be related to the rest of the database.

Just like a blueprint serves as a design for a house, mapping

relationships to relational database structures is part of creating

the “first-cut” database design that will serve as the basis for

further discussion among designers, developers, and database

administrators.

5



Tell Me / Show Me

Rules for Relationships

A relationship creates one or more foreign-key columns in

the table at the many side.

We use the short name of the table to name the foreign-key

column. In the example on the next page, the foreign-key

column in the EMPLOYEES table is dpt_id for the

relationship with DEPARTMENT and epe_id for the

recursive relationship.

The foreign-key column is mandatory or optional,

depending on whether or not the relationship is required. In

the example, dpt_id is mandatory and epe_id is optional.

6



Tell Me / Show Me

Key Type Optionality Column

Name

pk * id

* name

* address

* birth_date

fk1 * dpt_id

fk2 o epe_id

EMPLOYEE

# id

* name

* address

* birth date

DEPARTMENT

# id

* name

belong to

composed ofthe manager

of

managed by


Name

pk * id

uk * name

foreign key refers to

foreign key refers to

EMPLOYEES (EPE)DEPARTMENTS (DPT)

Rules for Relationships Illustrated

7



Tell Me / Show Me

Mapping of Mandatory Relationship at the One Side

Relationships that are mandatory on the one side, or mandatory on

both sides, are mapped exactly the same way as a relationship that

is optional on the one side. The ER model is rich enough to capture

optionality at both ends of the relationship. However, the relational

model is limited in that a foreign-key constraint can enforce a

mandatory relationship only at the many end.

In the following example, the relational model cannot enforce that a

BAND must be composed of at least one MUSICIAN. The

optionality at the one end will have to be implemented through

additional programming.

8



Tell Me / Show Me

Key type Optionality Column

name

pk * id

* name

MUSICIAN

# id

* name

o instrument

BAND

# id

* name

BANDS (BAD)

Key type Optionality Column

name

pk * id

* name

o instrument

fk o bad_id

MUSICIANS (MSN)

Foreign

key

refers

to

a member of

composed of

Enforcing Optionality

9



Tell Me / Show Me

Mapping of Nontransferable Relationships

A nontransferable relationship in the conceptual model

means that the foreign-key column in the database table

cannot be updated. The foreign-key constraint cannot

enforce this in the database. Additional programming will be

needed to make sure that the database follows this business

rule. It is important to document these rules so that the team

remembers to write the appropriate code and enforce this

business rule.

10



Tell Me / Show Me

issued to

the recipient of

PAY CHECK

# id

* pay period

EMPLOYEE

# id

* name

Key Type Optionality Column Name

pk * id

* pay_period

fk * epe_id

PAYCHECKS (PCK)

The value in this

foreign-key

column cannot

be changed

Enforcing Nontransferable Relationships

11



Tell Me / Show Me

Mapping of Barred Relationships

A barred relationship is mapped to a foreign-key column

on the many side, just like any other M:1 relationship. In

this case, the foreign-key column plays a double role,

because it is also part of the primary key.

In the example, bak_number is a foreign-key column in

ACCOUNTS that refers to the primary key of BANKS. It is

also part of the primary key of ACCOUNTS.

12



Tell Me / Show Me


pk * act_nbr

* balance

* date_opened

pk,fk * bak_nbr

ACCOUNT

# number

* balance

* date opened

BANK

# number

* name

located in

the location of


pk * bank_number

name

ACCOUNTS (ACT)

BANKS (BAK)

refers

to

Mapping of Barred Relationships (continued)

13



Tell Me / Show Me

Cascade Barred Relationships

Hierarchies can lead to cascade barred relationships, where

the UID of the entity at the top of the hierarchy is carried all

the way down to the UID of the entity at the bottom of the

hierarchy. In the example, the UID of ROOM is composed of

the ROOM number, SUITE number, FLOOR number, and

BUILDING id. This is represented by the barred relationships.

When this is mapped to a relational model, it can result in

very long foreign-key column names, as they use the short

names of the originating tables as a prefix. The suggested

convention is never to use more than two table prefixes. In

the following example, the foreign-key column in ROOMS that

comes all the way from BUILDINGS is named sue_bdg_id,

instead of sue_flr_bdg_id.

14



Tell Me / Show Me

pk * rom_nbr

pk, fk * sue_nbr

pk, fk * sue_flr_nbr

pk, fk * sue_bdg_id

ROOM

# number

SUITE

# number

o tenant

FLOOR

# number

BUILDING

# id

* address

located within located within located within

the location of the location of the location of

pk * flr_nbr

pk, fk * bdg_id

pk * sue_nbr

pk, fk * flr_nbr

pk, fk * flr_bdg_id

o tenant

pk * id

* address

ROOMS (ROM) SUITES (SUE)

FLOORS (FLR) BUILDINGS (BDG)

Cascade Barred Relationships (continued)

15



Tell Me / Show Me

Cascade Barred Relationship Illustrated

Sample data for each table illustrates the cascade barred

relationships.

id address

100 40 Potters Lane

201 57G Maricopa Way

flr_nbr bdg_id

1 100

2 100

1 201

2 201

sue_nbr flr_nbr flr_bdg

15 2 100

25 2 100

5E 1 201

7B 2 201

rom_nbr sue_nbr sue_flr_nbr sue_bdg_id

1 15 2 100

2 15 2 100

1 7B 2 201

BUILDINGS

FLOORS

SUITES

ROOMS

16



Tell Me / Show Me

Mapping Many-to-Many Relationships

A M:M relationship is resolved with an intersection entity,

which maps to an intersection table. This intersection table

will contain foreign-key columns that refer to the originating

tables.

In the example, REVIEWS contains all the combinations that

exist between a CRITIC and a MOVIE.

17



Tell Me / Show Me


pk, fk1 * ctc_id

pk, fk2 * mve_id

* rating

REVIEW

* rating

CRITIC

# id

* name

MOVIE

# id

* title

pk * id

* name

pk * id

* title

CRITICS (CTC)

MOVIES (MVE)

REVIEWS (RVW)

Mapping Many-to-Many Relationships (continued)

18



Tell Me / Show Me

Mapping Many-to-Many Relationships (continued)

When transforming a 1:1 relationship, you create a foreign

key and a unique key. All columns of this foreign key are

also part of the unique key.

If the relationship is mandatory on one side, the foreign

key is created in the corresponding table. In the example,

bcp_code is the foreign-key column in SODA_BOTTLES

that refers to the primary key of BOTTLE_CAPS.

Bcp_code would also be unique within the

SODA_BOTTLES table.

19



Tell Me / Show Me

pk * id

* name

fk, uk * bcp_code

SODA BOTTLE

# id

* name

BOTTLE CAP

# code

* descriptionsealed with

the sealer for

pk * code

* description

SODA_BOTTLES (SBE) BOTTLE_CAPS (BCP)

Mapping Many-to-Many Relationships

20



Optional Many-to-Many

If the relationship is optional on both sides, you can choose

which table gets the foreign key. There are no absolute rules,

but here are some guidelines:

• Implement the foreign key in the table with fewer rows to

save space.

• Implement the foreign key where it makes more sense

for the business.

In the example, a car-rental agency would be more

concerned about cars than spaces, so it makes sense to put

the foreign key in CARS. However, in a parking-lot business,

the main object is the parking space. Therefore, it would

make sense to put the foreign key in SPACES.

Tell Me / Show Me

21



Tell Me / Show Me

pk * lic_plate

* model

fk, uk o spe_id

CAR

# license plate

* model

SPACE

# id

* descriptionparked in

the location for

pk * id

* description

pk * lic_plate

* model

pk * id

* description

fk, uk o car_lic_plate

Car-Rental Business

CARS (CAR) SPACES (SPE)

CARS (CAR) SPACES (SPE)

Parking-Lot Business

Business Rules for Optional Many-to-Many

22



Enforcing Many-to-One

If the relationship is mandatory at both ends, you have the

same limitation in the database as a M:1 relationship that is

mandatory at the one end. Therefore, you would need to

write additional code to enforce it.

Tell Me / Show Me

23



Tell Me / Show Me

Mapping Arcs

The entity that has the arc will map to a table that contains

foreign keys from the tables on the “one” end of the

relationships.

Note that even if the relationships in the arc are mandatory on

the many side, the resulting foreign keys have to be optional

(because one of them will always be blank).

24



Tell Me / Show Me

pk * id

* name

* date

* cost

o description

fk1 o pse_id

fk2 o phe_id

EVENT

# id

* name

* date

* cost

o description

PUBLIC SPACE

# id

* address

* rental fee

o comments

PRIVATE HOME

# id

* address

o comments

held at

the venue for

held at

the venue for

pk * id

* address

* rental_fee

o comments

pk * id

* address

o comments

EVENTS (EVT)PUBLIC_SPACES (PSE)

PRIVATE HOMES (PHE)

Mapping Arcs (continued)

25



Tell Me / Show Me


Since the arc represents exclusive relationships, additional

code is needed to enforce that only one of the foreign keys

has a value for every row in the table. A check constraint

stored in the database can easily do this. In the example, the

code for the check constraint would look like this:

CHECK (pse_id is not null AND phe_id is null)

OR (pse_id is null AND phe_id is not null)

If the relationships were fully optional, you would add:

OR (pse_id is null AND phe_id is null)

26



Tell Me / Show Me

id address rental fee comments

6 900 Chestnut St 100.00 No elevator

10 201 Union Highway 78.00 Church

basement

id address comments

15 4 Via Maria

20 677 Third Street Large projection TV

id name date cost description pse_id phe_id

42 Jones

reception

05 June 500 6

48 Morales

party

08 July 750 Surprise 40th 10

50 Brennan

dinner

12 July 400 Catered 20

Sample data for PUBLIC_SPACES

Sample data for PRIVATE_HOMES

Sample data for EVENTS


27



Tell Me / Show Me


The code checks that if there is a value for the public space

id (pse_id), then the column for private home id (phe_id)

must be empty. Conversely, if the public space id is NULL,

then there must be a value for the private home id. In a fully

optional relationship, additional code allows both the public

space id and the private home id to be null (the event is not

held at any venue).

28



Tell Me / Show Me

Terminology


Nontransferable relationship

Cascade barred relationship

Intersection entity

29



Objectives



transform 1:M and barred relationships


transform M:M relationships

• Transform 1:1 relationships


transform relationships in an arc

Summary

30



Summary

Practice Guide




Subtype Mapping

2

Subtype Mapping


What Will I Learn?

Objectives


• State and apply the table, column, identifiers,

relationship, and integrity constraint rules for mapping

supertype implementations



subtype implementations



supertype and subtype arc implementations

3

Subtype Mapping


Why Learn It?

Purpose

A carpenter who is building your dream house may know that

you will use different types of light bulbs all around the

house. However, if you do not provide information on where

certain types of light bulbs should be installed, you could end

up with an overly bright bedroom and a dimly lit kitchen!

Mapping supertypes and subtypes makes sure that the right

information gets stored with each type.

4

Subtype Mapping


Tell Me / Show Me

Supertype Implementation: Single Table

This choice produces a single table for the implementation of

the supertype entity and its subtypes. This is also called

"single-table (or one-table) implementation."

Rules

1. Tables: Only one table is created, independent of the

number of subtypes.

2. Columns: The single table gets a column for all the

attributes of the supertype, with the original optionality.

5

Subtype Mapping


Tell Me/ Show Me

Supertype Implementation: Single Table (continued)

The table also gets a column for each attribute belonging to

the subtype, but the columns all become optional.

Additionally, a mandatory column should be created to act as

a discriminator column to distinguish between the different

subtypes of the entity. The value it can take is from the set of

all the subtype short names (FTE, PTE, OTR in the

example). This discriminator column is usually called

<table_short_name>_type, in the example epe_type

6

Subtype Mapping


Tell Me / Show Me

DEPARTMENTS (DPT)

pk * id

EMPLOYEE

# id

* first name

* last nameDEPARTMENT

# id

managed by

FULL TIME

* salary

PART TIME

* hourly rate

the manager of

AGENCY

# id

assigned to

the home for

employed by

the source of

AGENCIES (AGY)

pk * id

EMPLOYEES (EPE)


Name

pk * id

* first_name

* last_name

o salary

o hourly_rate

fk1 * dpt_id

fk2 o agy_id

* epe_type

fk3 o mgr_id


(continued)

7

Subtype Mapping


Tell Me / Show Me


Rules

3. Identifiers: Unique identifiers transform into primary and unique

keys.

4. Relationships: Relationships at the supertype level transform

as usual. Relationships at subtype level are implemented as

optional foreign-key columns.

5. Integrity constraints: A check constraint is needed to ensure

that for each particular subtype, all columns that come from

mandatory attributes are not null.

8

Subtype Mapping


Tell Me / Show Me


In the ER model, salary is mandatory for full-time

employees and hourly rate is mandatory for part-time

employees. When the EMPLOYEE supertype is

implemented as a single table in the relatonal model, these

attributes become optional. A check constraint is needed to

enforce the business rules modeled in the ERD.

9

Subtype Mapping


Tell Me/ Show Me


In the example, the code for the check constraint would look

like this:

CHECK (epe_type = ‘FTE’ and salary is not null and

hourly_rate is null and agy_id is null)

OR (epe_type = ‘PTE’ and salary is null and hourly_rate is

not null and agy_id is not null)

10

Subtype Mapping


Tell Me/ Show Me


The code checks that if it is a full-time employee (epe_type

= ‘FTE’), then there must be a value in the salary column

and the hourly_rate and agy_id columns must be empty.

Conversely, if it is a part-time employee (epe_type =

‘PTE’), then there must be value in hourly_rate, and an

agy_id, but salary must be left blank.

11

Subtype Mapping


Tell Me / Show Me

id first_name last_name salary hourly_rat

e

dpt_id agy_id epe_type epe_i

d

2000 Joan Merrick 50000 10 FTE 111

111 Sylvia Patakis 90000 10 FTE

2101 Marcus Rivera 65.00 10 17 PTE 111

2102 Hector Chen 75.00 25 17 PTE 45

45 Rajesh Vishwan 90000 25 FTE

Sample Data for EMPLOYEES


(continued)

12

Subtype Mapping


Tell Me / Show Me

When Do You Choose the Single-Table/Supertype

Implementation?

The single-table implementation is a common and flexible

implementation. It is the one you are likely to consider first

and is especially appropriate where:

• Most of the attributes are at the supertype level.

• Most of the relationships are at the supertype level.

• Business rules are globally the same for the subtypes.

13

Subtype Mapping


Tell Me / Show Me

Subtype Implementation: Two Table

This is also called "two-table implementation." You create a

table for each of the subtypes. So, in reality, you could have

more than two tables, if you had more than two subtypes.

Rules

1. Tables: One table per first-level subtype.

2. Columns: Each table gets a column for all attributes of

the supertype with the original optionality.

3. Each table also gets a column for each attribute

belonging to the subtype, also with the original

optionality.

14

Subtype Mapping


Tell Me/ Show Me

Subtype Implementation: Two Table (continued)

Rules

4. Identifiers: The primary UID at the supertype level creates a

primary key for each table. Secondary UIDs of the supertype

become unique keys in each table.

5. Relationships: All tables get a foreign key for a relationship at

the supertype level, with the original optionality. For

relationships at the subtype levels, the foreign key is

implemented in the table it is mapped to. Original optionality is

retained.

15

Subtype Mapping


Tell Me / Show Me

Key

Type

Optionality Column

Name

pk * id

* material

* sleeve_length

* neck_size

o collar_style

fk1 o tlr_id

fk2 * mnv_id

SHIRTS (SHT) SHOES (SHE)

CLOTHING

# id

* material

SHIRT

* sleeve length

* neck size

o collar style

SHOE

* size

* buckle style

o heel height

MANUFACTURER

# id

TAILOR

# id

COBBLER

# id

Key

Type

Optionality Column

Name

pk * id

* material

* size

* buckle_style

o heel_height

fk1 o clr_id

fk2 * mnv_id

refers to manufacturers refers to tailors refers to cobblersrefers to manufacturers

produced by

the producer of

altered by

the alterer of

repaired by

the repairer of


16

Subtype Mapping


Tell Me / Show Me

Subtype Implementation: Two Table (continued)

In the example, a separate table would be created for SHIRTS and

SHOES.

id material sleeve_length neck_size collar_style mnr_id tlr_id

10 linen 33 16 button down 65 14

11 wool 32 15.5 nehru 65 22

14 cotton 33 15.5 60 22

id material size buckle_style heel_height mnr_id clr_id

3 leather 7.5 monkstrap 1.5 75 44

7 canvas 8 velcro 1 70 44

Sample Data for SHIRTS

Sample Data for SHOES

17

Subtype Mapping


Tell Me / Show Me

When to Consider Subtype Implementation

Subtype implementation may be appropriate when:

• Subtypes have very little in common. There are few attributes

at the supertype level and several at the subtype level.

• Most of the relationships are at the subtype level.

• Business rules and functionality are quite different between

subtypes.

• How tables are used is different -- for example, one table is

being queried while the other is being updated.

18

Subtype Mapping


Tell Me / Show Me

Modeling the Supertype as an Arc

A supertype entity and its subtypes can be modeled as an arc

relationship. Here again is the ERD with the supertype and

subtypes.

CLOTHING

# id

* material

SHIRT

* sleeve length

* neck size

o collar style

SHOE

* size

* buckle style

o heel height

MANUFACTURER

# id

TAILOR

# id

COBBLER

# id

produced by

the producer of

altered by

the alterer of

repaired by

the repairer of

19

Subtype Mapping


Tell Me / Show Me

Model An Arc

Illustrated

In this ERD, we

have redrawn the

CLOTHING

supertype and its

subtypes of SHIRT

and SHOE as

standalone entities

with each one

having mandataory

1:1 relationships

with the supertype.

The relationships

are in an arc.

CLOTHING

# id

* material

MANUFACTURER

# idproduced by

the producer of

SHIRT

* sleeve length

* neck size

o collar style

TAILOR

# id

SHOE

* size

* buckle style

o heel height

COBBLER

# id

a supertype

of

a

subtype

of

altered by

the alterer

of

a supertype

of

a

subtype

of

repaired by

the

repairer

of

20

Subtype Mapping


Tell Me / Show Me

Supertype and Subtype (Arc) Implementation

This choice produces one table for every entity. The

supertype table has a foreign key for each subtype table.

These foreign keys represent exclusive relationships. They

are optional because only one of them can have a value for

each row in the table.

Rules

1. Tables: As many tables are created as there are

subtypes, as well as one for the supertype.

2. Columns: Each table gets a column for all attributes of the

entity it is based on, with the original optionality.

21

Subtype Mapping


Tell Me/ Show Me

3. Identifiers: The primary UID of the supertype level creates

a primary key for each of the tables. All other unique

identifiers become unique keys in their corresponding

tables.

4. Relationships: All tables get a foreign key for a relevant

relationship at the entity level, with the original optionality.

5. Integrity constraints: Two additional columns are created

in the table based on the supertype. They are foreign-key

columns referring to the tables that implement the

subtypes. The columns are optional because the foreign

keys are in an arc. An additional check constraint is

needed to implement the arc. The foreign-key columns

are also unique keys because they implement a

mandatory 1:1 relationship.

Supertype and Subtype (Arc) Implementation (continued)

22

Subtype Mapping


Tell Me / Show Me


pk * id

* material

fk1, uk1 o sht_id

fk2, uk2 o she_id

fk3 * mnr_id


pk * id

* sleeve_length

* neck_size

o collar_style

fk1 o tlr_id


pk * id

* size

* buckle_style

o heel_height

fk1 o clr_id

CLOTHING (CTG)

SHIRTS (SHT)

SHOES (SHE)

refers to shirts

refers to shoes

refers to

manufacturers

refers to tailors

refers to

cobblers

Supertype and Subtype (Arc) Implementation (continued)

23

Subtype Mapping


Tell Me / Show Me

When to Consider Both a Supertype and Subtype (Arc)

Implementation

This implementation is rarely used, but it could be appropriate

when:

• Subtypes have very little in common and each table

represents information that can be used independently. For

example, when the CLOTHING table gives all global

information, and both SHOES and SHIRTS give specific

information, and the combination of global and specific

information is hardly ever needed.

• Business rules and functionality are quite different between

all types.

• How tables are used is different.

24

Subtype Mapping


Tell Me / Show Me

Terminology


Supertype implementations

Subtype implementations

Arc implementations

25

Subtype Mapping




• State and apply the table, column, identifiers, relationship,

and integrity constraint rules for mapping supertype

implementations


and integrity constraint rules for mapping subtype

implementations


and integrity constraint rules for mapping supertype and

subtype arc implementations

Summary

26

Subtype Mapping


Summary

Practice Guide





INSTRUCTOR NOTES SECTION 11 – Introduction to Relational Database Concepts Lesson Slide 1: Introduction to Relational Database Concepts Lesson Preparation This lesson talks about relational databases, primary keys, foreign keys, and data integrity. This will help with the conceptual to physical mapping later in this section, and with the transition to SQL in the upcoming sections. Encourage the students to realize that they are learning a new set of terminology. An entity is not a table, and an attribute is not a column. We will be transforming (exchanging) one set of objects (ER conceptual modeling constructs) into another (data design physical model constructs). What to Watch For If anyone asks, the word “relation” is an abstract mathematical term used in set theory. A mathematical relation has the same logical properties as a table in a database. This is the origin of the term “relational database”, i.e. a database consisting of a set of relations (i.e., tables). Connections Remind students that they have seen integrity rules before. These are the business rules that sometimes cannot be represented in the conceptual model and therefore must be documented. This is the reason for the documentation – to make sure that the programmers write extra code to enforce these rules in the database! Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – A relational database is a database… Relational database: Collections of objects or relations, set of operators to act on those relations, and data integrity for accuracy and consistency. Explain that each row of data describes an employee. Each column is an attribute of that employee. If we wanted to find out the last name and department number of employee number 210, we would need to access the third row in the table, and then find the values for fname and dept_no for that row. But how do we find the correct row in the first place? Would we have to go through the whole table and look at every row? Answer: No. (Move on to next page.)



Instructor Resource Guide Slide 5: Tell Me / Show Me – Structured query language (SQL)… Ask students if they understand the SQL code just by reading it. They should have some ideas because of its English-like syntax. Slide 6: Tell Me / Show Me – Employees (table) No instructor notes for this slide Slide 7: Tell Me / Show Me – To find all the employees in department… Explain that “*” after SELECT means we want all the columns in the table. Slide 8: Tell Me / Show Me – Employees (table) SQL allows us to access the whole table or just parts of the table, depending on what comes after SELECT and what is specified in the WHERE clause. Slide 9: Tell Me / Show Me – Primary Key (table) Primary key: A constraint which ensures that the column contains no null values and uniquely identifies each row of the table. Point out that in ACCOUNTS, BANK_NO is not unique and ACCT_NO is not unique. However, the combination of BANK_NO and ACCT_NO is unique. Slide 10: Tell Me / Show Me – Primary Key (table) Ask students to point out the rows in each table that violate the rule that no part of the primary key can be null. Answer: Second row in EMPLOYEES, second row in ACCOUNTS. These rows violate entity integrity. Slide 11: Tell Me / Show Me – A table can have more than one column… Candidate key: More than one column or combination of columns that could serve as the table’s primary key. Ask students what makes EMPLOYEE_ID and PAYROLL_ID good candidates for the primary key? Answer: They are both unique and not null. Slide 12: Tell Me / Show Me – Select one candidate key to be… Unique key: An integrity constraint that requires every value in a column or set of columns be unique. Ask students why having alternate or unique keys can be useful? Answer: It’s another way to locate a record. If you forget your employee ID, but know your payroll ID (or have a payroll stub with the ID on it), then you can still access your employee record.



Instructor Resource Guide Slide 13: Tell Me / Show Me – Foreign Key Foreign key: A column or set of columns that refers to a primary key in the same table or another table. Point out that if the foreign key (DEPARTMENT_ID) in EMPLOYEES has a value of 10, then there needs to be a row in DEPARTMENTS with a DEPARTMENT_ID of 10. Otherwise, it is a violation of referential integrity. You can also explain this in business terms, by saying that an employee can’t belong to a department that doesn’t exist. Slide 14: Tell Me / Show Me if a foreign key is a part of a primary… Point out that in the example, SHELF_NO is part of the primary key of BOOKS. It is also a foreign key to SHELVES. Since it is part of the PK of BOOKS, it cannot be null. Slide 15: Tell Me / Show Me – Column Integrity Row: An entry in a table, consisting of values for each appropriate column. Column: An implementation of an attribute or relationship in a table. Explain to students that the datatype for the columns BANK_NO, ACCT_NO, and BALANCE is numeric. The number in parentheses indicates how big the numeric value can be. A datatype of date means the value must be a valid date. “Not null” in the Optionality column means that the column is mandatory. Which rows in the table violate column integrity? Answer: Second and fourth rows Slide 16: Tell Me / Show Me – Summary of Data-Integrity Rules No instructor notes for this slide Slide 17: Tell Me / Show Me – (table) The first three shown here are a summary of the data-integrity rules we’ve covered. The last one (an example of user-defined integrity) has not been covered yet, but students should understand its importance by now. Slide 18: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 19: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 21: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 11 – Basic Mapping: The Transformation Process Lesson Slide 1: Basic Mapping: The Transformation Process What to Watch For Students may not see a great difference between the conceptual model and the relational design at this point. They may ask: why not create table definitions from the start? Explain that simple entities (like the ones they will see in this lesson) are very similar to relational tables. However, once we get to foreign keys, arcs, and subtypes, there will be differences. Also, remind them that when they create a conceptual model, they are focused on the business and its rules. When they create a database design, the focus will be on database issues of storage, speed of transactions, security, etc. For example, in a Data Warehouse, the physical model is often deliberately de-normalized to give faster performance. Although these are important issues, they should not be considered before or above the business requirements. Data modeling pays attention to the business requirements, regardless of implementation. You may have the fastest and most secure database in the world, but if it doesn’t meet your business requirements, it’s not going to be of much use. Connections In earlier lessons students have modeled a number of business scenarios. Tell students to imagine that the client has approved their model and now wants a system built based on the model, using a relational database. Transforming that model into a database design would be the next phase. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Stress that in this and the next two lessons we are NOT building the house (or creating the database). We are transforming the terminology we have used to build our conceptual model into the equivalent relational database terminology, following naming conventions and restrictions. Slide 4: Tell Me / Show Me – Review of Relational Tables This and the next few slides are a review of the concepts covered previously.

Slide 5: Tell Me / Show Me – Review of Relational Tables (continued) No instructor notes for this slide Slide 6: Tell Me / Show Me – Review of Relational Tables (continued) No instructor notes for this slide



Instructor Resource Guide Slide 7: Tell Me / Show Me – Review of Relational Tables (continued) Remind students that unique keys can be null, unlike primary keys.

Slide 8: Tell Me / Show Me – Review of Relational Tables (continued) No instructor notes for this slide Slide 9: Tell Me / Show Me – Review of Relational Tables (continued) No instructor notes for this slide Slide 10: Tell Me / Show Me – The conceptual model is transformed… Transform: To change the elements of an ERD (entities, attributes, relationships) into database elements (tables, attributes, foreign keys). Differentiate between the EMPLOYEE entity in the ERD (conceptual model) and the diagram of the EMPLOYEES table, which represents the definition of the table in the relational model (physical implementation). The notations in the table diagram will be explained later in this lesson. Slide 11: Tell Me / Show Me – Terminology Mapping Map: To associate the elements of an ERD (entities, attributes, relationships) with database elements (tables, attributes, foreign keys). Explain that analysis and design are phases of the system life cycle (to be discussed more later). When designing a system, analysis precedes design. Data modeling is done in the analysis phase. When you are satisfied that you have captured the business requirements in the data model, you move on to the design phase, where the ERD is mapped to a physical implementation. Slide 12: Tell Me / Show Me – Terminology Mapping Stress again that in these simple examples there is a one-to-one mapping between conceptual and physical terminology (for example one entity becomes one table) but that this will not always be true in more complex models. Slide 13: Tell Me / Show Me – Table Diagram Notations Unlike the mandatory table name, a short name is an optional convenience. Slide 14: Tell Me / Show Me – Table Diagram Notations (continued) No instructor notes for this slide Slide 15: Tell Me / Show Me – Naming Conventions for Tables and Columns Stress that these are conventions, not rules. However, one reason for using a plural table name is to avoid possible errors later when the table is created. For example, the Oracle database will not allow the creation of a table named ORDER, because ORDER is a reserved word ın SQL (SELECT .... ORDER BY ...).



Instructor Resource Guide Slide 16: Tell Me / Show Me – Naming Conventions for Tables and Columns (continued) Stress that these are conventions, not rules. We replace spaces by underscores in column names because the Oracle database will not allow spaces (and hyphens etc.) within a column name. Slide 17: Tell Me / Show Me – Naming Conventions: Short Names In this and the next slide, stress that short names are NOT mandatory, simply useful. The suggested “rules” are one of several possible conventions for determining short names. Do not spend too much time on them. Slide 18: Tell Me / Show Me – Naming Conventions: Short Names (continued) These rules do not guarantee uniqueness, but experience has proved that duplicated names are relatively rare. In the case of identical short names, just add a number to the one that is used less. Example: CTR and CTR1. Slide 19: Tell Me / Show Me – Naming Conventions: Short Names (continued) These rules do not guarantee uniqueness, but experience has proved that duplicated names are relatively rare. In the case of identical short names, just add a number to the one that is used less. Example: CTR and CTR1. Slide 20: Tell Me / Show Me – Naming Restrictions with Oracle Note that Oracle table and column names can contain underscores but not hyphens. For example, SALES_ORDERS is a valid table name but SALES-ORDERS is not. Explain that all database systems make recommendations on naming objects (such as tables). If they do not use an Oracle database, they should still decide on a naming convention and make sure it is compatible with the database system that they have chosen. Slide 21: Tell Me / Show Me – Naming Restrictions with Oracle (continued) You may want to show the students how to use Technet where the lists of reserved words in Oracle 10g can be found. This site requires you to sign up, but it is free. It's a valuable source of technical information on all Oracle products. Technet is currently located at www.oracle.com/technology, but this could change in future. A safer bet is to go to www.oracle.com and look for links to “Oracle Technology Network”. Slide 22: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 23: Summary – In this lesson you have learned to: No instructor notes for this slide



Instructor Resource Guide Slide 24: Summary - Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 11 – Relationship Mapping Lesson Slide 1: Relationship Mapping Connections Remind them that the barred relationships to ORDER LINE indicate that the UID of ORDER and FOOD ITEM participate in the UID of ORDER LINE. When the entity is mapped to table ORDER_LINES, we see that the foreign keys from FOOD_ITEMS and ORDERS (fim_number and odr_number, respectively) make up the composite primary key of ORDER_LINES. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Why Learn It? (continued) No instructor notes for this slide Slide 5: Tell Me / Show Me – Rules for Relationships No instructor notes for this slide Slide 6: Tell Me / Show Me – (diagrams & tables) When transforming M:1 relationships, it may be helpful to visualize the crow’s foot “pulling” the UID of the entity on the one side into the entity on the other side (the crow’s feet side). Point out that the ER diagram captures the relationships between entities, expressed in business terms. When the conceptual model is transformed, the relationships become foreign-key columns, but the relationship name itself is not carried over. The database design will be the basis for the system, but starting with a conceptual model ensures that the tables, columns, and constraints created in the database are relevant to the business and fulfill its requirements. A database contains objects such as tables, columns, and constraints. A data modeler sees how these objects are related from a business perspective. “In the example, dpt_id is mandatory, and epe_id is optional.” Give the business example so that students understand why the epe_id is optional. Does the president of a company have a manager? Since epe_id implements the recursive relationship in EMPLOYEE, it is probably better renamed to mgr_id. Decisions like this can be made at this stage of mapping.



Instructor Resource Guide Slide 7: Tell Me / Show Me – Mapping of Mandatory Relationship at the One Side No instructor notes for this slide Slide 8: Tell Me / Show Me – (diagrams & tables) No instructor notes for this slide Slide 9: Tell Me / Show Me – Mapping of Nontransferable Relationships Nontransferable relationship: information that cannot be updated. Slide 10: Tell Me / Show Me – (diagrams & tables) In the example, a paycheck may not be transferred to another employee. This means that the epe_id, which is the foreign-key column in the table PAYCHECKS, cannot be updated. Slide 11: Tell Me / Show Me – Mapping of Barred Relationships No instructor notes for this slide Slide 12: Tell Me / Show Me – (diagrams & tables) Help students visualize the data in ACCOUNTS. The act_nbr alone would not be unique within the table, but the combination of act_nbr and bak_nbr would be. Slide 13: Tell Me / Show Me – Cascade Barred Relationships Cascade barred relationships: A series of relationships implying that the unique identifier of each entity in the chain is carried down to the entity on the next level. The UIDs and resulting primary keys are highlighted in different colors to help you trace a UID through the hierarchy. Slide 14: Tell Me / Show Me – (diagrams & tables) The UIDs and resulting primary keys are highlighted in different colors to help you trace a UID through the hierarchy. The primary key of FLOORS now becomes a composite of flr_nbr and bldg_id. The primary key of SUITES is a composite of sue_nbr, flr_nbr, and flr_bldg_id. Point out that the composite is one primary key (a table is only allowed to have one PK). In this case, it is also one foreign key for each table, even if that key is a composite of multiple columns. The foreign key in SUITES is the combination of flr_nbr and flr_bldg_id. The foreign key in ROOMs is a combination of sue_nbr, sue_flr_nbr, and sue_bdg_id.



Instructor Resource Guide Slide 15: Tell Me / Show Me – Sample data for each table illustrate the… Ask students: What is the primary key of ROOMS? Answer: The combination of rom_nbr, sue_nbr, sue_flr_nbr, and sue_bdg_id. Verify that the combination of all four is what makes a row unique. Point out that any three columns alone or in combination does not make a unique value. Trace the id all the way from BUILDINGS (id) to FLOORS (bdg_id) to SUITES (flg_bdg_id) to ROOMS (sue_bdg_id). Slide 16: Tell Me / Show Me – Mapping M:M Relationships Intersection entity: The product of the resolution of a many to many relationship. Note the subscript notation on each foreign key (fk1 and fk2). This is meant to show that each foreign-key column references the primary key of a different table. This differs from previous examples where the foreign-key column (or columns) references the primary key of a single table. Slide 17: Tell Me / Show Me – (diagrams & tables) Note the subscript notation on each foreign key (fk1 and fk2). This is meant to show that each foreign-key column references the primary key of a different table. This differs from previous examples where the foreign-key column (or columns) references the primary key of a single table. Slide 18: Tell Me / Show Me – Mapping 1:1 Relationships Clarify the necessity for a unique key on bcp_code if necessary. Remind them of the relationship in the conceptual model: “Each bottle cap may be the sealer for one and only one soda bottle.” If you had a bottle cap with code AB55, that would be unique in the SODA_BOTTLES table, because it can occur only in one instance or one row of the table. Slide 19: Tell Me / Show Me – (diagrams & tables) Clarify the necessity for a unique key on bcp_code if necessary. Remind them of the relationship in the conceptual model: “Each bottle cap may be the sealer for one and only one soda bottle.” If you had a bottle cap with code AB55, that would be unique in the SODA_BOTTLES table, because it can occur only in one instance or one row of the table.



Instructor Resource Guide Slide 20: Tell Me / Show Me – Mapping 1:1 Relationships (Optional or…) Mandatory 1:1 relationships are rare. In most cases, this will be modeled as a single table, without a need for a 1:1 relationship. However, if you need to clarify the limitation of 1:1 mandatory at both ends, you can revisit the earlier slide on m:1 mandatory on the “one” end in this lesson. Slide 21: Tell Me / Show Me – (diagrams & tables) No instructor notes for this slide Slide 22: Tell Me / Show Me –Mapping Arcs Point out that pse_id and phe_id in the EVENTS table are optional, but the relationships in the arc are mandatory (each EVENT must be held at one VENUE). A check constraint will enforce this mandatory relationship. Slide 23: Tell Me / Show Me – (diagrams & tables) No instructor notes for this slide Slide 24: Tell Me / Show Me – Mapping Arcs (continued) You may need to explain the concept of a check constraint, as opposed to additional programming that is needed to enforce mandatory relationships on the “one” end (as in the previously discussed M:1 or 1:1). A check constraint is programming code that can be stored in the database. It can enforce simple rules that apply to a single row in the table (such as comparing values or ensuring that they are null or not null). This is the case with the arc. In the case of a mandatory one end of a M:1 or 1:1 relationship, we have to check that if a row is entered in one table (the master), a row must also be entered in another table (the child, or detail). A check constraint cannot span two tables or different rows in the same table. It cannot prevent insert, update, or delete operations. This is why additional programming (instead of a check constraint) is necessary. Slide 25: Tell Me / Show Me – (diagrams & tables) No instructor notes for this slide Slide 26: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 27: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 28: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 11 – Subtype Mapping Lesson Slide 1: Subtype Mapping Lesson Preparation You may want to review supertypes and subtypes briefly. Use the DJ and Global Foods ERDs as examples. What to Watch For Students may get bogged down in the arc implementation of a supertype. The best way to understand it is to redraw the data model using an arc instead of a supertype. Then transform the model as an arc. The tricky part is that the relationships in the arc are 1:1 instead of M:1, which is usually seen in an arc. 1:1 relationships are not modeled that often; usually the data modeler will use one entity instead of two. For this reason, modeling supertypes as arcs is not that common either. Arcs are best used to express exclusive relationships, not a “type of” condition. Let students know that most of the time, the single-table implementation is used. Connections Section 12, Lesson 3, also discusses mapping 1:1 relationships, as well as arcs. Students may need to review this to understand why a 1:1 relationship results in a unique key on the mandatory side. For a review of supertype modeling, refer to Section 4, Lesson 3. For a review of arcs and exclusive relationship modeling, refer to Section 7, Lesson 3. Slide 2: What Will I Learn? Tell students that there are three ways to implement supertypes in the database. All three will be discussed in this lesson. Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – Supertype Implementation: Single Table Supertype: A means of classifying an entity that has subtypes. Slide 5: Tell Me / Show Me – Supertype Implementation: Single Table (continued) No instructor notes for this slide



Instructor Resource Guide Slide 6: Tell Me / Show Me – (diagrams & tables) Point out that salary and hourly_rate are both optional, even if the ERD has them as mandatory. dpt_id can remain mandatory, because it comes from the relationship to the supertype EMPLOYEE. agy_id comes from a relationship to the subtype and has to become optional. epe_type is the discriminator column. It can have values of FTE or PTE. Notice that mgr_id represents the recursive relationship for EMPLOYEE. It is a foreign key column and would normally be named epe_id, after the parent table. However, it makes sense to rename it at this stage, to make it easier to understand. Slide 7: Tell Me / Show Me – Supertype Implementation: Single Table (continued) A check constraint is necessary to ensure that (epe_type = ‘FTE’ and salary is not null and hourly_rate is null and agy_id is null) OR (epe_type ‘PTE’ and salary is null and hourly_rate is not null and agy_id is not null). epe_id is the employee identifier of each employee’s manager. A note about the OTHER subtype: An OTHER subtype is recommended in the conceptual model to ensure that the subtypes are exhaustive. However, by the time we start the design phase, we should have done extensive analysis to determine if another subtype is truly needed. If so, then this subtype must be named, and its attributes specified. If not, then the OTHER subtype is not part of the transformation process. Slide 8: Tell Me / Show Me – Supertype Implementation: Single Table (continued) Explain that a check constraint is activated when you insert or update a row in the table. So, if you tried to update the row for Marcus Rivera by putting a value in the salary column, the check constraint would prevent you from succeeding. Similarly, if you wanted to enter a new row for a full-time employee (epe_type = FTE), but tried to enter a value for agy_id, the check constraint would prevent the insert. Slide 9: Tell Me / Show Me – Supertype Implementation: Single Table (continued) No instructor notes for this slide Slide 10: Tell Me / Show Me – Supertype Implementation: Single Table (continued) No instructor notes for this slide Slide 11: Tell Me / Show Me – (diagrams & tables) Explain that a check constraint is activated when you insert or update a row in the table. So, if you tried to update the row for Marcus Rivera by putting a value in the salary column, the check constraint would prevent you from succeeding. Similarly, if you wanted to enter a new row for a full-time employee (epe_type = FTE), but tried to enter a value for agy_id, the check constraint would prevent the insert.



Instructor Resource Guide Slide 12: Tell Me / Show Me – When Do You Choose the Single-Table/Supertype Implementation? This is the implementation used most often. It is elegant and appropriate for most situations and should be considered as the first choice. Usually you would create a view for every subtype, showing only the columns that belong to that particular subtype. The correct rows are selected using a condition based on the discriminator column. Example: CREATE OR REPLACE FULL_TIME_VW AS Select id, first_name, last_name, salary, dpt_id, epe_id from EMPLOYEES where epe_type = ‘FTE’; Slide 13: Tell Me / Show Me – Subtype Implementation: Two Table Subtype: Something an entity may be split into based on common attributes and/or relationships. Slide 14: Tell Me / Show Me – Subtype Implementation: Two Table (continued) No instructor notes for this slide Slide 15: Tell Me / Show Me – (diagrams & tables) Point out that the original optionality of the attributes and relationships is carried over to the columns and foreign keys, so there is no need for a check constraint as there is in the one-table implementation. If there were a need to have unique values of the primary key (ID) across both tables, then additional programming would be necessary. Slide 16: Tell Me / Show Me – Subtype Implementation: Two Table (continued) Point out that id, material, and mnr_id come from attributes in OR relationships to the supertype. Therefore, they appear in both tables. Slide 17: Tell Me / Show Me – When to Consider Subtype Implementation Usually you would create an additional view that represents the supertype, showing all columns of the supertype and the various subtypes. The view SELECT statement must use the UNION operator. Slide 18: Tell Me / Show Me – Modeling the Supertype as an Arc We have previously discussed how supertypes and subtypes can also be drawn as an arc. We are illustrating this with the example, so that students can better understand the arc implementation.



Instructor Resource Guide Slide 19: Tell Me / Show Me – In this ERD, we have redrawn the CLOTHING… Discuss why the relationships are 1:1 mandatory and exclusive:

• Each SHIRT must be one piece of CLOTHING. Each SHOE must be one piece of CLOTHING.

• Conversely, each piece of CLOTHING must be either a SHOE or a SHIRT but not both.

Point out that most of the time, the data modeler would choose to model this with a supertype (previous diagram) because of the 1:1 mandatory nature of the relationships. Recall that 1:1 mandatory relationships usually indicate that a single entity is needed. Arcs are more often used when the exclusive relationships are 1:M. Slide 20: Tell Me / Show Me – Supertype and Subtype (Arc) Implementation Arc: A curved line used to represent an exclusive relationship in an entity-relationship diagram. Slide 21: Tell Me / Show Me – 3. Identifiers: The primary UID of the… No instructor notes for this slide Slide 22: Tell Me / Show Me – (diagrams & tables) Point out that it is not necessary to remodel the supertype as an arc (as we did), in order to choose to do an arc implementation. However, it makes sense to do so for clarity. If necessary, recall the previous lesson on mapping an arc. You would need a check constraint on CLOTHING to enforce that (sht_id is not null and she_id is null) OR (sht_id is null and she_id is not null). Slide 23: Tell Me / Show Me – When to Consider Both a Supertype and Subtype (Arc) Implementation Although you would hardly use them, you could consider creating additional views that represent the supertype and subtypes in full. Slide 24: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 25: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 26: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 11 – Introduction to Oracle Application Express (OAE) Lesson Slide 1: Introduction to Oracle Application Express (OAE) Lesson Preparation For this lesson, we will perform the Try It/Solve It activity (use OAE) before we explain what happened in Tell Me/Show Me. Oracle Application Express User Guide – This document will help you become familiar with how to use Oracle Application Express and each of its components from and end user’s perspective. If you would like to learn more about the administrative capabilities or teacher capabilities of Oracle Application Express, please refer to the Oracle Application Express Teacher Guide. To log into Oracle Application Express, go to http://iacademy.oracle.com Enter your school, username, and password information. This information was given to you via email from [email protected]. If you did not receive this information, please email: [email protected]. You must be a registered and paid DM/SQL instructor. Students will get their account information from their teacher. What to Watch For Students will quickly catch on to Oracle Application Express and creating tables. Encourage them but set a standard for appropriateness.

Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 5: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 11 – Introduction to Relational Database Concepts Lesson

Vocabulary Part One: Identify the vocabulary word for each definition below. Primary key A constraint which ensures that the column contains

no null values and uniquely identifies each row of the table.

Foreign key A column or set of columns that refers to a primary key in the same table or another table.

Row An entry in a table, consisting of values for each appropriate column

Column An implementation of an attribute or relationship in a table

Unique key An integrity constraint that requires every value in a column or set of columns be unique.

Relational database Collections of objects or relations, set of operators to act on those relations, and data integrity for accuracy and consistency.

Candidate key More than one column or combination of columns that could serve as the table’s primary key

Part Two: Identify the integrity rules below. Column-integrity rule A column must contain only values consistent with

the defined data format of the column Data-integrity rule Define the relationally correct state for a database;

they ensure that users can perform only those operations that leave the database in a correct, consistent state

Entity integrity rule A primary key must be unique and no part of the primary key can be null

Referential integrity rule A foreign key must match an existing primary key value (or else be null)

User-defined integrity rule The data stored in a database must comply with the rules of the database



Instructor Resource Guide Try It / Solve It 1. Data Integrity in the DJ Database

Examine the sample data for these tables in the DJs on Demand database. Check for entity, referential and column integrity. Identify any data-integrity violations. Assume that all date columns should have a date format and all amount (cost) columns should have a number format.




Solution: CLIENTS table Entity integrity: ID for Sarika Patel should not be null. EVENTS TABLE Column integrity: Cost for Collins wedding (event id = 17) is not numeric. Column integrity: Date for Collins rehearsal dinner (event id = 25) is not a valid date format. Referential integrity: There is no client 77 in the CLIENTS table (event id = 50). Referential integrity: There is no theme corresponding to “BB” in the THEMES table (event id = 15).



Instructor Resource Guide SECTION 11 – Basic Mapping: The Transformation Process Lesson

Vocabulary Part One: Identify the vocabulary word for each definition below. Transform To change the elements of an ERD into database

elements Map To associate the elements of an ERD with database

elements

Try It / Solve It 1. Transform the following entities into table definitions, using suitable naming

conventions.

Solution: Explain that we are not creating tables; we are creating definitions of tables. The physical implementation of the table will be done in a later lesson using HTML DB. Check that students have recognized the composite UID in BANK ACCOUNT. Although we are not too concerned with foreign key relationships at this stage, some students will recognize that bank id in BANK ACCOUNT is probably a foreign key to a BANK entity.



Instructor Resource Guide 2. Match the ERD elements to their corresponding database elements.

Analysis Design

Attribute (1) Entity (2) ER Model (3) Instance (4) Primary UID (5) Relationship (6) Secondary UID (7)

Column (1) Foreign key (6) Physical design (3) Primary key (5) Row (4) Table (2) Unique key (7)

3. Identify the table diagram notations listed below.

• “pk” Primary key • “fk” Foreign key • “uk” Unique key • “*” Mandatory • “o” Optional

4. Create short names for the terms below based on the naming conventions rules.

• Academic major AMR • Undergraduate UDE • Class CLS

5. Identify what is wrong with each of the table names below.

• 1997classes Can't start with numbers: must start with a letter

• Schedule_of_classes_spring_2003

Name is more than 30 characters long

• Financial Aid deadlines! Name cannot contain spaces or special characters

6. (Optional Practice: Global Fast Foods)

This practice is step 11 in the Global Fast Foods project.



Instructor Resource Guide SECTION 11 – Relationship Mapping Lesson

Vocabulary Directions: Identify the vocabulary word for each definition below. Nontransferable relationship A relationship in a database where the foreign key

column in the database table cannot be updated Cascade barred relationship A series of relationships implying that the unique

identifier of each entity in the chain is carried down to the entity on the next level

Intersection entity The product of the resolution of a many to many relationship.

Try It / Solve It Relationship Mapping The following entities were mapped to tables in the previous lesson: SHIFT, REGULAR MENU, PROMOTIONAL MENU, FREQUENT DINER CARD. Refer to the completed Global Fast Foods model and map the following entities: FOOD ITEM ORDER ORDER LINE 1. Transform relationships into foreign-key columns.

Use as many rows as necessary in the following table diagram.

Column Name

Optionality (“*” or “o”)

Key Type (pk, uk, fk)




2. Indicate if a check constraint or additional programming is needed to enforce the

relationship in the database. Under each table diagram, write the conditions that the check constraint or program has to ensure.

For example:

“To enforce exclusive relationships, a check constraint is needed to make sure that (column A is not null and column B is null) OR (column A is null and column B is not null).” “To enforce a nontransferable relationship, additional programming is needed to make sure that the <foreign key column> cannot be updated.”

Solution: A check constraint is needed to enforce: either (rmu_code is null and pmu_code is not null) OR (rmu_code is null and pmu_code is not null). Additional programming is needed to ensure that stf_id is not updateable. This will enforce the non-transferability of the relationship between ORDER and STAFF.



Instructor Resource Guide SECTION 11 – Subtype Mapping Lesson

Try It / Solve It 1. Transform the PARTNER supertype in the DJ model, using the supertype or single-

table implementation.

Solution: After going through the activity, you may want to conduct the following discussion to check for understanding:

• Remind students that they need a discriminator column. What would this column be named? (Answer: pnr_type.) What are the allowable values for this column? (Answer: EPR, DJ, MNR.)

• Remind students that they need a check constraint. What would it check for? (Answer: (pnr_type = ‘EPR’ and expertise is not null and specialty is null and authorized_expense_limit is null) or (pnr_type = ‘DJ’ and expertise is null and specialty is not null and authorized_expense_limit is null) or (pnr_type =’MNR’ and expertise is null and specialty is null and authorized_expense_limit is not null).)

• What does the foreign-key column pnr_id refer to? (Answer: the PARTNERS table.)

• What relationship was it mapped from? (Answer: the recursive relationship in PARTNER.)

• What does it represent? (Answer: the id of the partner’s manager.) 2. Transform the STAFF supertype in the Global Fast Foods model, using the subtype or

two-table implementation.

Solution:

Global Fast Foods




After going through the activity, you may want to conduct the following discussion to check for understanding:

• What does the foreign-key column mnr_id refer to? (Answer: the MANAGERS table.)

• What relationship was it mapped from? (Answer: the recursive relationship in STAFF.)

• What does it represent? (Answer: the id of the manager.) 3. Identify the database rules for each part of the database implementations below.

Supertype implementations • Table • Column • Identifiers • Relationship • Integrity constraint rules

Subtype implementations

• Table • Column • Identifiers • Relationship • Integrity constraint rules

Arc implementations

• Table • Column • Identifiers • Relationship • Integrity constraint rules

Solution: Supertype implementations

Table: Only one table is created, independent of the number of subtypes. Column: The single table gets a column for all the attributes of the supertype, with the original optionality. Identifiers: Unique identifiers transform into primary and unique keys. Relationship: Relationships at the supertype level transform as usual. Relationships at subtype level are implemented as optional foreign-key columns. Integrity constraint rules: A check constraint is needed to ensure that for each particular subtype, all columns that come from mandatory attributes are not null.




Subtype implementations Table: One table per first-level subtype. Column: Each table gets a column for all attributes of the supertype with the original optionality. Identifiers: The primary UID at the supertype level creates a primary key for each table. Secondary UIDs of the supertype become unique keys in each table. Relationship: All tables get a foreign key for a relationship at the supertype level, with the original optionality.

Arc implementations

Table: As many tables are created as there are subtypes, as well as one for the supertype. Column: Each table gets a column for all attributes of the entity it is based on, with the original optionality. Identifiers: The primary UID of the supertype level creates a primary key for each of the tables. All other unique identifiers become unique keys in their corresponding tables. Relationship: All tables get a foreign key for a relevant relationship at the entity level, with the original optionality. Integrity constraint rules: Two additional columns are created in the table based on the supertype. They are foreign-key columns referring to the tables that implement the subtypes. The columns are optional because the foreign keys are in an arc. An additional check constraint is needed to implement the arc. The foreign-key columns are also unique keys because they implement a mandatory 1:1 relationship.




SECTION 11 – Introduction to Oracle Application Express (OAE) Lesson

Try It / Solve It Creating the MUSIC table You will be using an application called Oracle Application Express to log on to the database, create tables, and insert data. Your instructor will walk you through the process of logging on and using the application. 1. You will be creating a database table called MUSIC. The table data is provided here.

Can you identify the column names? How many rows does the table have? What is the unique identifier of this table? Can you give an example of an instance of the MUSIC table?

MUSIC_ID ARTIST_NAME TYPE 1 BOB MARLEY REGGAE 2 BRITNEY SPEARS POP 3 NSYNC POP 4 SHAGGY REGGAE 5 JIMMY CLIFF REGGAE 6 KID ROCK RICJ 7 THIRD WORLD REGGAE 8 LENNY KRAVITZ ROCK 9 YELLOW MAN REGGAE

Your instructor will step you through the process of creating the MUSIC table using Oracle Application Express. You can use the music.sql script that your instructor will provide or enter the CREATE TABLE statement yourself. SQL statement: CREATE TABLE MUSIC ( MUSICID NUMBER(2) NOT NULL, ARTIST_NAME VARCHAR2(20), TYPE VARCHAR2(13), CONSTRAINT MUSIC_PRIMARY_KEY PRIMARY KEY (MUSICID));




After you create your table, you will populate it with data. You can use the music.sql script that your instructor provides or enter the INSERT statements yourself. What did we just do? We used SQL to create a table in the database and to insert data into the table. Solution: Review the Oracle Application Express User's Guide. Step through it with students, making sure each student can log on successfully. Give each student a copy of the MUSIC table. Have them answer the questions ABOVE. Answers: Column names are musicid, artist_name, type. There are nine rows in the table. The unique identifier is musicid. Any row in the table can be an example of an instance. Students can either enter the music-table statements themselves in Oracle Application Express or use the music.sql script with the statements already written. The CREATE TABLE statement must be run first and then each INSERT statement entered one at a time. Explain that SQL stands for structured query language, and they are going to use SQL commands to create a table in the database.

a. Give each student a copy of the music.sql file. b. Walk them through the SQL syntax: CREATE TABLE <table name> is the

SQL command. In the example, the table name is MUSIC. This command must be followed with a list of columns and their datatype and any constraints. This list must be enclosed in parentheses. The most common datatypes are varchar(length), number(length), and date. In the example: MUSICID is the first column, with datatype NUMBER(2); ARTIST_NAME is the second column with datatype of varchar(20). NOT NULL specified after a column name and datatype means that the column is mandatory. In the example: MUSICID is mandatory. After the list of columns, you can also specify a constraint for the table, with the word CONSTRAINT. In the example: the constraint is a primary key on the column MUSICID. Each SQL statement ends with a semicolon.

c. Log on to HTML DB. Wait until all students have successfully logged on. d. Step students through the process for entering the CREATE TABLE statement

in the SQL window. e. If they prefer to run the script, instruct them to use the command @music.sql. f. HTML DB should return a “table created successfully” statement. Don't

continue until all students have successfully created the MUSIC table.




Explain to students that the INSERT statements must be entered and run one at a time. Explain to students that they used Oracle Application Express to log on to the Oracle database and ran a SQL script (or entered SQL statements) to create a table and enter data into the database.



Introduction to Oracle Application Express

2

Oracle Application Express


What Will I Learn?

Objectives


• Log into the Oracle Application Express practice

environment

• Create a table using a script in Oracle Application

Express

• Enter sample data into the table created

• Execute a defined query on the table to validate

successful data insertion

3



Why Learn It?

Purpose

You have drawn the plans for your dream house and then

transformed it into a physical design for the house. The next

step is to actually build the house. You will need tools to do

this.

Oracle Application Express (OAE) is a tool that will allow you

to build tables in an Oracle database.

4





• Log into the Oracle Application Express practice

environment

• Create a table using a script in Oracle Application Express

• Enter sample data into the table created

• Execute a defined query on the table to validate successful

data insertion

Summary

5



Summary

Practice Guide




SQL Introduction: Querying the Database

2



What Will I Learn?

Objectives


• Apply the rules of SQL to display all columns and a

subset of columns specified by criteria

• Add new data with a different value in the “type”

column

• Refine the SQL query to display only those rows that

have data with the new type

3



Why Learn It?

Purpose

What if every time you got dressed for school, you had to take out

all of your clothes from every dresser and closet in your whole

house? You might be late for school and you’d certainly have a lot

to clean up! Accessing data in a database is a similar process if

you don’t limit what you’re looking for with criteria.

When retrieving information from a database, you will often have to

find a subset of the data, based on specific criteria. Becoming

familiar with SQL will help you get the information you need.

4



Tell Me / Show Me

DESCRIBE Command

The DESCRIBE command displays the structure of the

table. The syntax is:

DESCRIBE <table name>;

5



Tell Me / Show Me

Basic SELECT Statement

The SELECT * command returns all the rows in a

table. The syntax is:

SELECT * FROM <table name>;

6



Tell Me / Show Me

Select Statement With a Condition

To return a subset of the data, modify the SELECT

statement. The syntax is:

SELECT <column name 1, column name 2,

etc.>

FROM <table name>

WHERE <condition>;

7



Tell Me / Show Me

Inserting Data

Using the INSERT command, you can add a row of data

to the table. The syntax is:

INSERT INTO <table name>

VALUES (value 1, value 2, value 3, etc);

8



Tell Me / Show Me

Terminology


Modification

Subset

Syntax

9



Summary



• Apply the rules of SQL to display all columns and a

subset of columns specified by criteria

• Add new data with a different value in the “type” column

• Refine the SQL query to display only those rows that

have data with the new type

10



Summary

Practice Guide




Basic Table Modifications

2



What Will I Learn?

Objectives


• Add a new column to a table

• Use the DELETE and ALTER TABLE commands to

correct mistakes or make revisions to a table

3



Why Learn It?

Purpose

What if you were building a house and decided to

change the placement of a window or door? If you

change your mind or make a mistake, there should be

a way to remove or change a feature of the house.

Modifying a table addresses the same need when

building a database. SQL anticipated this need and

has commands to perform these functions.

4



Tell Me / Show Me

ALTER TABLE Syntax

To add a new column to a table, use the ALTER

TABLE command. The syntax is:

ALTER TABLE <table name>

ADD (<new_column_name> <data type>);

5



Tell Me / Show Me

Drop A Column

To drop a column from a table, use the ALTER TABLE

command. The syntax is:

ALTER TABLE <table name>

DROP COLUMN <column_name>;

6



Tell Me / Show Me

Delete a Row

To delete a row from a table, use the DELETE

command. The syntax is:

DELETE from <table name>

WHERE <column_name> = 'some value‘;

7



Summary



• Add a new column to a table

• Use the DELETE and ALTER TABLE commands to

correct mistakes or make revisions to a table

8



Summary

Practice Guide




System Development Life Cycle

2



What Will I Learn?

Objectives


• List and describe the different stages of the system-

development life cycle

• Identify the role of data modeling in the system-


• Relate the project tasks to the different stages of the

system-development life cycle

3



Why Learn It?

Purpose

When you build a house, you draw up the plans before

you start construction. During construction, you lay the

foundation before you start putting up walls. You finish

all the major construction before you start decorating.

The architect, the builder, and the decorator work

accordingly so that they do their jobs at the appropriate

time.

A knowledge of the tasks associated with each stage of

the system-development life cycle will help you plan a

project better and be a productive member of the team.

4



Tell Me / Show Me

System Development Life

Cycle

From concept to production,

you can develop a database

by using the system-

development life cycle,

which contains multiple

stages of development. This

top-down, systematic

approach to database

development transforms

business-information

requirements into an

operational database.

D

O

C

U

M

E

N

T

A

T

I

O

N

Strategy and Analysis

Design

Build

Transition

Production

5



Tell Me / Show Me


Study and analyze the

business requirements.

Interview users and

managers to identify the

information requirements.

Incorporate the enterprise

and application mission

statements as well as any

future system

specifications.

EMPLOYEE

# id

* first name

* last name

* date of birth

DEPARTMENT

# id

* description

o budget

belong to

composed of

6



Tell Me / Show Me


(continued)

Build conceptual models of

the system. Transfer the

business narrative into a

graphical representation of

business-information

needs and rules. Confirm

and refine the model with

the analysts and experts.

EMPLOYEE

# id

* first name

* last name

* date of birth

DEPARTMENT

# id

* description

o budget

belong to

composed of

7



Tell Me / Show Me

Design

Transform the model

developed in the strategy

and analysis phase. Map

entities to tables, attributes

to columns, relationships

to foreign keys, and

business rules to

constraints.

EMPLOYEES (EPE)

pk * id

* first_name

* last_name

o date_of_birth

fk * dpt_code

DEPARTMENTS (DPT)

pk * id

* description

refers to

o budget

8



Tell Me / Show Me

Build

Write and execute the commands to

create the tables and supporting objects

for the database.

Populate the tables with data.

Develop user documentation, help text,

and operations manuals to support the

use and operation of the system.

9



Tell Me / Show Me

Transition

Conduct user-acceptance testing.

Convert existing data and parallel

operations. Make any modifications

required.

Production

Roll out the system to the users.

Operate the production system. Monitor

its performance and enhance and refine

the system.

10



Tell Me / Show Me

Terminology


Parallel operations

Populate

System development life cycle

User- acceptance testing

11



Summary



• List and describe the different stages of the system-


• Identify the role of data modeling in the system-


• Relate the project tasks to the different stages of the

system-development life cycle

12



Summary

Practice Guide





INSTRUCTOR NOTES

SECTION 12 – SQL Introduction: Querying the Database Lesson Slide 1: SQL Introduction: Querying the Database Lesson Preparation Have each student access the link to the basic SQL commands. What to Watch For Students will quickly learn the basic SQL commands and want to do more at this point. Explain to them that getting data from more than one table and other operations will have to wait a few weeks. Connections Retrieving data is like interviewing your clients. You are trying to get specific information from that giant database of a client! Recall the animal-shelter activity when students interviewed the director. Students had to understand what the director knew about the functions of the animal shelter so that they could properly meet the director’s needs. Ask them what they would do now if the director wanted a report of all animals currently in the shelter? Possible responses: Use SQL to get it out of a database. Or build the database with create tables, enter data, and then extract data using a SELECT * FROM Animals. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – The DESCRIBE command displays the structure… Syntax: The rules governing the formation of statements in a programming language. Write the DESCRIBE music syntax on the board. Ask students to enter the SQL command. Discuss what the statement means and what it returns. Slide 5: Tell Me / Show Me – The SELECT * command returns all the rows… Write the SELECT * FROM music syntax on the board. Ask students to enter the SQL command. Discuss what the statement means and what it returns.



Instructor Resource Guide Slide 6: Tell Me / Show Me – To return a subset of the data, modify the SELECT… Explain that the <condition> often takes the form of column name + operator (=, >, <, IS NULL, IS NOT NULL, etc.).” Slide 7: Tell Me / Show Me – Using the INSERT command, you can add a row… Ask what would happen if you tried to insert a row with values (9, ‘ERIC CLAPTON’, ‘ROCK’). Answer: You would get an error because there is already a row with musicid = 9. Musicid is the primary key of the table and must be unique. Slide 8: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 9: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 10: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 12 – Basic Table Modifications Lesson Slide 1: Basic Table Modifications Connections Retrieving data is like interviewing your clients. You are trying to get specific information from that giant database of a client! Recall the animal-shelter activity when students interviewed the director. Students had to understand what the director knew about the functions of the animal shelter so that they could properly meet the director’s needs. Ask them what they would do now if the director wanted a report of all animals currently in the shelter? Possible responses: Use SQL to get it out of a database. Or build the database with create tables, enter data, and then extract data using a SELECT * FROM Animals. Slide 2: What Will I Learn? Add Column: Mention that this type of change to a table is different from adding or removing data. You’re changing the structure. This is called DDL (data definition language – you’ll learn more about this in SQL). It’s good to mention this at this point so that, when students hear it later, it will be familiar. Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – To add a new column to a table, use… You may want to demonstrate this on your computer if you can share your screen with the students. Add a column to the MUSIC table using the ALTER TABLE command, – but misspell the column (e.g., COUNTRI instead of COUNTRY). Slide 5: Tell Me / Show Me – To drop a column from a table, use… Demonstrate this by dropping the misspelled column. Have students suggest how to add the column again. Ask for the syntax. Slide 6: Tell Me / Show Me – To delete a row from a table, use the… Point out that numbers do not require quotes around them (example: 10), but text does (example: ‘ERIC CLAPTON’). Slide 7: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 8: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 12 – Project Overview and Getting Started Lesson Slide 1: Project Overview and Getting Started Lesson Preparation Up to this point, students have learned data-modeling concepts and tested their understanding by solving problems and answering questions at the end of each lesson. Interspersed with the data-modeling content have been lessons on foundation skills or professional skills needed to succeed in today's competitive marketplace (What Is a Consultant? Overcoming the Fear Factor, Leaders in IT, What About Me?, The Changing Nature of Work). Throughout the course, students have also demonstrated basic presentation skills (IOUG Case Presentation, Animal Shelter Activity). The final presentation project challenges students to “put it all together.” Using a relevant real-world example, the intent of the project is to apply data-modeling concepts as they are learned and to teach presentation skills essential for business. Working in groups of two or three, students will choose a scenario based on a real-world business example where a database would be needed. Acting as consultants to this “business,” students will define the need for the database, identify the components, create an ERD, write documentation, and present their database design. Several project ideas are provided, but students can elect to explore a project of its own choosing. Each group will present its project results as a culminating activity for this course. Review the list of project ideas. It may be difficult for some students to identify a specific project. Your task is to help students identify an area of interest: I know I would not like to…, I am not interested in..., I have always been interested in..., etc. Give students the project list and ask them to read through the suggested topics. Have them place a “+” next to their top five choices and a “-” next to five topics they are not interested in. At this point, encourage students to choose what they find interesting and not what their best friend likes. Organize students into groups of two or three. Suggestion about forming groups: Don't reveal how you will assign the groups. After students have made their five highest and lowest choices, ask one student to verbally announce their highest choices. See if someone else also had one of these choices on his/her list. These two students form a team and compare their other choices. They then try to find another student who also shares their choice – these will become the groups. You also can choose to have them draw numbers so that it is randomized. Give student groups time to refine or design their own topic. It is important that students choose a topic they are interested in and are committed to completing. Let them know that changing their project is not an option once started. Alternatively, you can choose a specific project and assign it to the class. You may want to have them work with a project whose solution you are familiar with.



Instructor Resource Guide Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Explain that presentation skills are essential to becoming a productive employee. Presentation skills build the foundation for success as a future IT professional. Research shows that 83% of the information we take in is by sight; only 17% is from taste, touch, smell, or hearing. Data modeling is a process that relies on presentation skills to refine the information requirements of the client as well as to demonstrate a completed database design for final approval. Slide 4: Why Learn It? (continued) No instructor notes for this slide Slide 5: Tell Me / Show Me – You will now have the opportunity… No instructor notes for this slide Slide 6: Tell Me / Show Me – Acting as consultants to this business, you will… Explain that the animation presents a slice of the process they will be going through in the next seven days. Their work will be more detailed, and they will take more time than the animation, but this will give them a preview of what they’ll be doing Slide 7: Tell Me / Show Me – Presentation Project Ideas (purpose) Explain the purpose of the project to the students. Have them review the list of project ideas. If they want to come up with their own topic, they are free to do so, provided that they let you know, and that you approve it for their project. Slide 8: Tell Me / Show Me – Presentation Project Ideas (begin) No instructor notes for this slide Slide 9: Tell Me / Show Me – Presentation Project Ideas (starting points) No instructor notes for this slide Slide 10: Tell Me / Show Me – Presentation Project Ideas Environmental No instructor notes for this slide Slide 11: Tell Me / Show Me – Presentation Project Ideas Environment (continued) No instructor notes for this slide Slide 12: Tell Me / Show Me – Presentation Project Ideas Historical No instructor notes for this slide Slide 13: Tell Me / Show Me – Presentation Project Ideas Historical (continued) No instructor notes for this slide



Instructor Resource Guide Slide 14: Tell Me / Show Me – Presentation Project Ideas Business No instructor notes for this slide Slide 15: Tell Me / Show Me – Presentation Project Ideas Science No instructor notes for this slide Slide 16: Tell Me / Show Me – Presentation Project Ideas Humanities No instructor notes for this slide Slide 17: Tell Me / Show Me – Written Documentation Print and hand out the documentation example. Details of the written documentation will be covered in another lesson. For now, it is good for the students to have an actual hard copy of what they are expected to produce. Slide 18: Tell Me / Show Me – This Final Presentation Rubric will be used… Discuss the Final Presentation Rubric. Students must know what is expected and this may help them make a committed choice of a topic. Slide 19: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 20: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 12 – Project Management: Final Presentation Checkpoint Lesson Slide 1: Project Management: Final Presentation Checkpoint Lesson Preparation Most of the class time today should allow students to make progress on their project. They need to refine and finalize their ERDs. A project-management tracking grid will be presented to the students as a way to track their progress. Print out copies of the final project-tracking grid for the students. They will fill this out over the course of the project. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Why Learn It? (continued) No instructor notes for this slide Slide 5: Tell Me / Show Me – A well-managed project has a better chance of… Hand out copies of the final project-tracking grid and review it with students. Point out that this is a way to organize all the tasks that need to be done for the final presentation. Slide 6: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 7: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 12 – SQL Introduction: Querying the Database Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Subset A set contained within another set.

Modification A change or revision.

Syntax The rules governing the formation of statements in a

programming language.

Try It / Solve It Basic SQL Commands 1. Your instructor will give you a copy of some basic SQL commands and will discuss

them with the class. Enter the commands in Oracle Application Express to see the results.

a. Enter two or three rows of data with a new type (CLASSICAL, NEW AGE, JAZZ

– your choice). Then retrieve only the rows of data with this new music type. b. Experiment on your own with variations of the command – retrieve different

columns and different rows (specific artists, types, etc.).

Solution: Give each student a copy of the basic SQL commands. Step through each command with the students. Have them enter the command and experiment on their own with variations of the commands provided.



Instructor Resource Guide SECTION 12 – Basic Table Modifications Lesson Try It / Solve It 1. Add at least five new rows and two new columns to the MUSIC table. If you make

mistakes, use the DELETE and ALTER commands to correct them.

Solution: Suggest some new columns, such as rating (they can assign their own rating system), comments, etc., but encourage students to make up their own. Note that some students will want to add a column named “song.” Point out that song would probably have multiple values, but they can call it “example song,” or “best-selling song,” etc. Have them recall the rules of data modeling at this point. Students can get frustrated when commands don't work. Make sure they know how to read the error messages. Don't be alarmed if they create something and delete it by accident. The music.sql script can always recreate the original table and data.



Instructor Resource Guide SECTION 12 – Project Overview and Getting Started Lesson Try It / Solve It 1. Decide on a topic for your group. 2. Discuss the specific business problems that you want to solve. 3. Start creating a first-cut ERD. Solution: Advise students that they should limit the ERD to five to six entities. They need to scope out their project realistically, because they have a little more than a week to put everything together.



Instructor Resource Guide SECTION 12 – Project Management: Final Presentation Checkpoint Lesson Try It / Solve It 1. Final Presentation Progress Report

Use the class time to make progress on your final presentation. Revise and finalize your ERD. Make sure you have all attributes defined, UIDs identified, relationships named and so on. Use subtypes, arcs and hierarchies if applicable.

2. Obtain a copy of the Final Presentation Project Tracking form from your teacher. Fill

in the project tracking grid to document your current progress. Solution: Work with each group. Have them fill out their final project-tracking grid and show you where they are in the project timeline. Remind them that they will create database tables from their ERD in two days. Note: If you feel your students will not have time to complete the database tables, you may consider requiring only the ERD and all documentation. You will be able to assess their progress and abilities. The next lesson will discuss the system-development lifecycle. After that they will map their ERDs to a table design and create the database tables using Oracle Application Express.



Anatomy of a SQL Statement

2



What Will I Learn?

Objectives


• Match projection, selection, and join with their

correct functions/ capabilities

• Create a basic SELECT statement

• Use the correct syntax to display all rows in a

table

• Use the correct syntax to select specific

columns in a table, modify the way data is

displayed and/or perform calculations using

arithmetic expressions and operators

3



What Will I Learn?

Objectives (continued)

• Formulate queries using correct operator

precedence to display desired results

• Define a null value

• Demonstrate the effect null values create in

arithmetic expressions

• Construct a query using a column alias

4



Why Learn It?

SELECT Keyword

SELECT is one of the most important, if not

the most important keyword in SQL. You use

SELECT to retrieve information from the

database.

When you learn how to use SELECT, you’ve

opened the door to the database.

Imagine a database containing information

about movies such as title, genre, studio,

producer, release date, series, country,

language, rating, running time, and so on.

What if you only wanted the titles of movies

created in India? The SELECT statement

allows you to search for specific data.

sdm_s16_l01_a01

5



Tell Me / Show Me

SELECT Statement

The SELECT statement retrieves information from the database.

The syntax for a SELECT statement is as follows:

SELECT <column_name(s)>

FROM <table_name>;

In its simplest form, a SELECT statement must include the

following:

• A SELECT clause, which specifies the columns to be

displayed

• A FROM clause, which specifies the table containing the

columns listed in the SELECT clause

6



Conventions

SELECT title

FROM d_songs;

Throughout this course, the following will be used:

• A keyword refers to an individual SQL statement. For

example, SELECT and FROM are keywords.

• A clause is a part of a SQL statement. For example, SELECT

title is a clause.

• A statement is a combination of the two clauses. For example,

SELECT title FROM d_songs is a statement.

Tell Me / Show Me

7



Tell Me / Show Me

Capabilities of SELECT

Statements

Projection: Used to choose

columns in a table

Selection: Used to choose

rows in a table

Table 2: Projection

Table 2: Selection

8



Tell Me / Show Me

Projection and Selection

SELECT salary

FROM employees

WHERE last_name like ‘Smith’;

Projection

Selection

ID FIRST_NAME LAST_NAME SALARY

10 John Doe 4000

20 Jane Jones 3000

30 Sylvia Smith 5000

40 Hai Nguyen 6000

9



Tell Me / Show Me

Joining Tables Together

Table 1 Table 2

Join

Join: Used to

bring together

data that is stored

in different tables

by creating a link

between them.

You will learn

about joins later

in the course.

10



Tell Me / Show Me

Selecting All Columns

You can display all the

columns of data in a table

by using an asterisk

symbol (*) instead of a

column name in the

SELECT clause.

In the following example,

all the columns in the

d_songs table are

selected.

SELECT *

FROM d_songs;

ID TITLE DURATIO

N

ARTIST TYPE_CODE

45 Its Finally

Over

5 min The Hobbits 12

46 I’m Going

to Miss My

Teacher

2 min Jane Pop 12

47 Hurrah for

Today

3 min The Jubilant Trio 77

48 Meet Me at

the Altar

6 min Bobby West 1

49 Lets

Celebrate

8 min The Celebrants 77

50 All These

Years

10 min Diana Crooner 88

11



Tell Me / Show Me

Selecting All

Columns (continued)

You can also display

all the columns in a

table by listing them

individually.

SELECT id, title,

duration, artist,

type_code

FROM d_songs;

ID TITLE DURATION ARTIST TYPE_CODE

45 Its Finally

Over

5 min The Hobbits 12

46 I’m Going to

Miss My

Teacher

2 min Jane Pop 12

47 Hurrah for

Today

3 min The Jubilant Trio 77

48 Meet Me at

the Altar

6 min Bobby West 1

49 Lets

Celebrate

8 min The Celebrants 77

50 All These

Years

10 min Diana Crooner 88

12



Tell Me / Show Me

Projecting Specific

Columns

If you want to PROJECT only

specific columns from a table

to be displayed, simply list

each of the column names

you want and separate each

name with a comma in the

SELECT clause.

SELECT id, title,

artist

FROM d_songs;

ID TITLE ARTIST

45 Its Finally Over The Hobbits

46 I’m Going to Miss My

Teacher

Jane Pop

47 Hurrah for Today The Jubilant Trio

48 Meet Me at the Altar Bobby West

49 Lets Celebrate The Celebrants

50 All These Years Diana Crooner

13



Tell Me / Show Me

Using Arithmetic Operators

Using a few simple rules and guidelines, you can

construct SQL statements that are both easy to read

and easy to edit. Knowing the rules will make

learning SQL easy.

You may need to modify the way in which data is

displayed, perform calculations, or look at what-if

scenarios. For example, "What if every employee

was given a 5% raise? How would that affect our

yearly profit figures?"

14



Tell Me / Show Me

Using Arithmetic Operators (continued)

These types of calculations are all possible using arithmetic

expressions. You are already familiar with arithmetic expressions

in mathematics:

add (+), subtract (-) , multiply (*) and divide (/).

Note that using these operators does not create new columns in

the tables or change the actual data values. The results of the

calculations will appear only in the output.

15



Tell Me / Show Me

Using Arithmetic Operators

(continued)

The example shown uses the

addition operator to calculate a

salary increase of 300 for all

employees and displays a new

SALARY + 300 column in the

output.

SELECT last_name, salary,

salary + 300

FROM employees;

Putting in blank spaces before and

after an arithmetic operator will not

affect the output.

LAST_NAME SALARY SALARY + 300

King 24000 24300

Kochhar 17000 17300

De Haan 17000 17300

Whalen 4400 4700

Higgins 12000 12300

Gletz 8300 8600

Zlotkey 10500 10800

Abel 11000 11300

Taylor 8600 8900

Grant 7000 7300

16



Tell Me / Show Me

Precedence in Arithmetic Operators

Precedence is the order in which Oracle evaluates

different operators in the same expression. When

evaluating an expression containing multiple

operators, Oracle evaluates operators with higher

precedence before evaluating those with lower

precedence. Oracle evaluates operators with equal

precedence from left to right within an expression.

17



Tell Me / Show Me

Precedence in Arithmetic Operators (continued)

Arithmetic operators perform the mathematical operations

of Multiplication, Division, Addition and Subtraction. If

these operators appear together in an expression,

multiplication and division are evaluated first. So the order

is: * / + -.

An easy way to remember their operator precedence is the

mnemonic device:

My Dear Aunt Sally

18



Tell Me / Show Me


If operators within an expression are of the same

priority, then evaluation is done from left to right. You

can always use parentheses to force the expression

within parentheses to be evaluated first.

In the example tables shown on the next slide, what

are the differences in the output between the query

that used parentheses and the one that didn't?

19



Tell Me / Show Me


LAST_NAME SALARY 12 * SALARY + 100

King 24000 288100

Kochhar 17000 204100

De Haan 17000 204100

Whalen 4400 52900

Higgins 12000 144100

Gietz 8300 99700

… … …

Operator Precedence

Using Parentheses

LAST_NAME SALARY 12 * (SALARY + 100)

King 24000 289200

Kochhar 17000 205200

De Haan 17000 205200

Whalen 4400 54000

Higgins 12000 145200

Gietz 8300 100800

… … …

20



Tell Me / Show Me

NULL Values

In SQL, NULL is an interesting word. To understand NULL,

you have to know what NULL is and what NULL is not. NULL

is a value that is unavailable, unassigned, unknown, or

inapplicable.

NULL is not the same as a zero or a space. In SQL, a zero is

a number, and a space is a character.

Sometimes, you don’t know the value for a column. In a

database, you can store unknowns in your databases.

Relational databases use a placeholder called NULL or null

to represent these unknown values.

21



Tell Me / Show Me

NULL Values (continued)

If any column value

in an arithmetic

expression is null,

the result is null or

unknown.

If you try to divide by

null, the result is null

or unknown.

However, if you try to

divide by zero, you

get an error!

LAST_NAME JOB_ID SALARY COMMISSION_

PCT

King AD_PRES 24000

Kochhar AD_VP 17000

De Haan AD_VP 17000

Whalen AD_ASST 4400

Higgins AC_MGR 12000 .2

Gietz AC_ACC

OUNT

8300 .3

Zlotkey SA_MAN 10500 .2

Abel SA_REP 11000 .15

… … … …

Salaries and Commissions

22



Tell Me / Show Me

NULL Values (continued)

SELECT last_name, job_id, salary,

commission_pct, salary*commission_pct

FROM employees;

LAST_NAME JOB_ID SALARY COMMISSION_

PCT

SALARY*

COMMISSION_PCT

King AD_PRES 24000

Kochhar AD_VP 17000

De Haan AD_VP 17000

Whalen AD_ASST 4400

Higgins AC_MGR 12000 .2 2100

Gietz AC_ACCOUNT 8300 .3 3300

Zlotkey SA_MAN 10500 .2 1720

Abel SA_REP 11000 .15 1050

… … … …

Salaries and Commissions

23



Tell Me / Show Me

Aliases

An Alias is a way of renaming a column heading in the output.

Without aliases, when the result of a SQL statement is displayed,

the name of the columns displayed will be the same as the

column names in the table or a name showing a arithmetic

operation such as 12*(SALARY + 100).

You probably want your output to display a name that is easier to

understand, a more "friendly" name. Column aliases let you

rename columns in the output.

24



Tell Me / Show Me

Aliases (continued)

There are several rules when using column aliases to format

output.

A column alias:

• Renames a column heading

• Is useful with calculations

• Immediately follows the column name

• May have the optional AS keyword between the column

name and alias

• Requires double quotation marks if the alias contains

spaces, special characters or is case-sensitive

25



Tell Me / Show Me

Using Column Aliases

The syntax for aliases is:

SELECT * |column|expr [ AS alias], .....

FROM table;

Examples:SELECT last_name AS name,

commission_pct AS comm

FROM employees;

SELECT last_name "Name",

salary*12 AS "Annual Salary"

FROM employees;

NAME COMM

King

Kochhar

De Haan

Name Annual Salary

King 288000

Kochhar 204000

De Haan 204000

26



Tell Me / Show Me

Terminology


Arithmetic expression

Arithmetic operator

Clause

Column

Column alias

From clause

Join

NULL

Projection

Select clause

Selection

Select statement

Statement

27



Summary



• Match projection, selection, and join with their correct

functions/capabilities

• Create a basic SELECT statement

• Use the correct syntax to display all rows in a table

• Use the correct syntax to select specific columns in a table,

modify the way data is displayed and/or perform calculations

using arithmetic expressions and operators

• Formulate queries using correct operator precedence to

display desired results

• Define a null value

• Demonstrate the effect null values create in arithmetic

expressions

• Construct a query using a column alias

28



Summary

Practice Guide




Oracle Database Environment

2



What Will I Learn?


• Explain the features and benefits that

the Oracle 11g Database Environment

provides for businesses

• Locate information about Oracle

Corporation and its products and

services

• Relate the steps in the system

development life cycle (SDLC) to the

development and design of the Oracle

11g Database product and the data-

modeling processsdm_s16_l02_a01

3



Why Learn It?

Purpose

Have you ever wondered why product

manufacturers design new models every

year and consumers seek to buy them?

What have you purchased recently that is

an improvement over a previous product

you owned (a mobile phone, a mp3

player, a video game player).

Businesses like Oracle constantly seek to

develop new products to improve

information technology. As a member of

the Oracle Academy, you have the

opportunity to learn from one of the

world's leaders in information technology.

4



Tell Me / Show Me

Application

Follow along as the instructor reads the article "The

Making of Oracle Database 10g" by Barbara Assidi.

Try to identify similarities between what the Oracle

Corporation experienced in developing their database

product and what you experienced in designing and

developing a database in data modeling.

5



Tell Me / Show Me

Article Highlights

Highlights you should have noted from the article:

• "The planning phase commenced about two years

before coding began."

• "The biggest challenge isn't coming up with great ideas

to build into the database -- it's narrowing them down."

• "Writing the code that comprises the Oracle database is

a disciplined activity that begins with the creation of a

Functional Specification Document -- a document that

provides details about each new feature of the

database, complete with architectural diagrams."

6



Tell Me / Show Me

Article Highlights (continued)

Highlights you should have noted from the article

(continued):

• "We had checkpoint meetings every six weeks to make

sure the development managers were on top of the

project and on schedule.”

• "Things don't always go as planned and these meetings

give us a chance to anticipate problems and respond

quickly to events."

• "Early on, we developed a core document that distilled

the myriad features of the release into a statement of the

release's key messages."

• "We spent a lot of time on the language."

7



Tell Me / Show Me


The System Development Life Cycle (SDLC) is a step-by-

step process that database developers use to transform the

information needs of a business into a working operational

database.

8



Tell Me / Show Me

System Development Life Cycle (continued)

The steps in the SDLC include:

• Strategy and analysis: Study and analyze the

business requirements; build the data models

• Design: Map the design to tables

• Build and document: Create the tables and the

user documentation

• Transition: Test and refine the design; train users

• Production: Roll out the system for the users

9



Summary



• Explain the features and benefits that the Oracle 11g

Database Environment provides for businesses

• Locate information about Oracle Corporation and its

products and services

• Relate the steps in the system development life cycle

(SDLC) to the development and design of the Oracle

11g Database product and the data-modeling process

10



Summary

Practice Guide




Using Applications

2

Using Applications


What Will I Learn?

Objectives


• Distinguish between application software and system

software and give an example of each

• Demonstrate use of Oracle Application Express to

enter SQL statements that retrieve data

3

Using Applications


Why Learn It?

Purpose

Every day, in one way or another,

we come in contact with computer

applications.

If you checked your email today, it

was probably done using an

application. If you bought an item at

a grocery store, the clerk scanned

the item using an application that

calculated your bill and updated the

store inventory. In this course, you

will learn the syntax of SQL using

the application Oracle Application

Express.

sdm_s16_l03_a01

4

Using Applications


Tell Me / Show Me

Application Programs

Although computers have been around since before you

were born, their use for business and personal computing

didn't take place until application software programs were

developed. Application programs allowed the end user,

people like you and me, to be able to buy fully developed,

ready-to-use programs. It was no longer necessary to

know how the program worked, just that it did work and

accomplished what we wanted it to do.

5

Using Applications


Tell Me / Show Me

Application Programs (continued)

Application program software is different from system

software. System software consists of low-level

programs designed to interact with the computer

hardware. Operating systems, compilers, and system

utilities are examples of system software. In contrast,

application software includes programs for word

processing, databases, gaming, email, and graphics.

6

Using Applications


Tell Me / Show Me

Application Programs (continued)

Yahoo.com uses the Oracle database

to store data. Rather than having

everyone who wants to search the

database or retrieve email learn SQL,

an application has all the SQL (and

other coding languages) pre-

programmed into it. With a few mouse

clicks, users have access to all the

information they need.

sdm_s16_l03_a02

7

Using Applications


Tell Me / Show Me

Using Applications

An application is like a car. To drive a car, you need to

know enough to make it work. It has a friendly “shell” to

hide all the things you don’t need to know, such as how

the transmission works or how fuel like petrol or diesel is

used to make it run. Could you ever get your driver's

license if you had to know every detail of what makes a

car run?

8

Using Applications


Tell Me / Show Me


In this course, you will use Oracle Application Express.

This application enables many developers to build and

access applications as if they were running in separate

databases. With built-in features such as design themes,

navigational controls, form handlers, and flexible reports,

Oracle Application Express accelerates the application

development process.

9

Using Applications


Tell Me / Show Me

Oracle Application Express (continued)

Oracle Application Express has three components:

• SQL Workshop

• Application Builder

• Data Browser

To learn SQL, you will use the SQL Workshop component. To

design an application, you use Application Builder.

Your teacher will demonstrate how to use SQL Workshop so you

can get started learning SQL.

10

Using Applications


Tell Me / Show Me

Terminology


Application software

System software

11

Using Applications


Summary



• Distinguish between application software and system

software and give an example of each

• Demonstrate use of Oracle Application Express to

enter SQL statements that retrieve data

12

Using Applications


Summary

Practice Guide




Relational Database Technology

2



What Will I Learn?

Objectives


• Define and give an example of a relational database

• Identify table-key terms, including row, column, field,

primary key, and foreign key

• Relate the importance of databases to everyday life

3



Why Learn It?

Purpose

Databases are part of our everyday life even though most of the

time we don't even think about them.

If you have ever made an airline reservation, used an ATM

machine, or made a mobile-phone call, you've used a database.

In fact, many cities use intelligent traffic guiding system databases

to control stoplights. So the next time you're waiting at a red light,

it may be a database that is responsible for your delay!

In this lesson, you will learn more about databases and how

they're organized and created.

4



Tell Me / Show Me

Relational Databases

A relational database allows tables to be related by means of a

common field. As few as two tables can be considered a

relational database if they share a common field. Realistically,

databases used in business have many tables, each table

sharing a common field with another table. The D_SONGS table

shown is one of several tables in the DJs On Demand database

and just one example of the many tables that will be used in this

course.

ID TITLE ARTIST

45 Its Finally Over The Hobbits

46 I’m Going to Miss My

Teacher

Jane Pop

47 Hurrah for Today The Jubilant Trio

48 Meet Me at the Altar Bobby West

49 Lets Celebrate The Celebrants

50 All These Years Diana Crooner

5



Tell Me / Show Me

Relational Databases (continued)

To understand how important databases have become in today's

world, consider the following statistics:

• Currently 20% of the world's data resides in RDBMSs.

• In the next two years, databases are expected to grow larger

than 100 terabytes. A database this big would be able to store

100,000 copies of the Encyclopedia Britannica or 200,000

hours of music or about 10 billion web pages.

• Some of the top 10 world's largest databases using the Oracle

RDBMS are:

– France Telecom, 29.2TB -- a communications company (a TB is

a terabyte equivalent to 1,000 gigabytes)

– Amazon.com with, 13 TB -- selling books and merchandise

– The Claria Corporation,12TB -- Internet behavioral marketing

company tracking Internet user behavior

6



Tell Me / Show Me

Review Key Terms

Let’s review the following key terms:

• table -- basic storage structure

• column -- one kind of data in a table

• primary key -- unique identifier for each row

• foreign key -- column that refers to a primary-key column

in another table

• row -- data for one table instance

• field -- the one value found at the intersection of a row

and a column

7



Tell Me / Show Me

Properties of Tables

There are six properties of tables in a relational database:

Property 1: Entries in columns are single-valued

Property 2: Entries in columns are of the same kind

Property 3: Each row is unique

Property 4: Sequence of columns is insignificant

Property 5: Sequence of rows is insignificant

Property 6: Each column has a unique name

8



Tell Me / Show Me

Accessing Data in an RDBMS

A relational database-management system (RDBMS)

organizes data into related rows and columns.

To access the data in a database, you do not need to know

where the data is located physically nor do you need to

specify an access route to the tables.

You simply use structured query language (SQL)

statements and operators.

9



Tell Me / Show Me

Communicating with Databases

Working with the database is very similar to calling up and

talking to a friend on the phone. First, you must choose a

method to communicate (the phone). Once connected, you

ask your friend a question (a query). In response to your

question, your friend answers (return of data). Pretty simple,

most of us are experts at this.

In this class, our method of communication with the

database will be through Oracle Application Express. When

you ask a question using SQL, the application will return an

answer.

10



Tell Me / Show Me

Communicating With Databases (continued)

As shown in the diagram, communicating with an RDBMS is

accomplished by entering a SQL statement in Oracle Application

Express. The request is then sent to the Oracle Server (a database

running on a computer), the request is processed and the data returned

is displayed. In very large database systems, many users, servers and

tables make up the RDBMS.

SQL statement is entered.

SELECT department_name

FROM departments;

Oracle

server

Statement is sent to the Oracle Server.

Data is returned from the Oracle Server.

11



Tell Me / Show Me

Categories of SQL Statements

SQL statements are grouped into several categories

depending on the functions they perform. During this course,

you will learn how to use SQL to execute these statements.

The data retrieval statement retrieves data from the database

using the keyword SELECT.

There are four categories of SQL statements:

• Data manipulation language (DML)

• Data definition language (DDL)

• Transaction control language (TCL)

• Data control language (DCL)

12



Tell Me / Show Me

Categories of SQL Statements (continued)

Data manipulation language (DML)

DML statements begin with INSERT, UPDATE, DELETE or

MERGE and are used to modify the table data by entering

new rows, changing existing rows, or removing existing rows.

Data definition language (DDL)

DDL statements creates, changes, and removes data

structures from the database. The keywords CREATE,

ALTER, DROP, RENAME and TRUNCATE begin DDL

statements.

13



Tell Me / Show Me

Categories of SQL Statements (continued)

Transaction control language (TCL)

TCL statements are used to manage the changes made

by DML statements. Changes to the data are executed

using COMMIT, ROLLBACK and SAVEPOINT. TCL

changes can be grouped together into logical

transactions.

Data control language (DCL)

DCL keywords GRANT and REVOKE are used to give or

remove access rights to the database and the structures

within it.

14



Tell Me / Show Me

Terminology


Data control language (DCL)

Data definition language (DDL)

Data manipulation language (DML)

Field

Foreign key

Primary key

Relational database

Row

Table

Transaction control (TCL)

15



Summary



• Define and give an example of a relational database

• Identify table-key terms, including row, column, field,

primary key, and foreign key

• Relate the importance of databases to everyday life

16



Summary

Practice Guide




Working with Columns, Characters, and

Rows

2

Working with Columns, Characters, and Rows


What Will I Learn?

Objectives


• Apply the concatenation operator to link columns to other

columns, arithmetic expressions, or constant values to

create a character expression

• Use column aliases to rename columns in the query result

• Enter literal values of type character, number, or date into a

SELECT statement

• Define and use DISTINCT to eliminate duplicate rows

• Edit, execute, and save SQL statements in Oracle

Application Express

3



Why Learn It?

Purpose

If you were writing an article about the Olympics, you might

want to know how many different countries and how many

different athletes from each country were being

represented.

Having to go through lists and lists of participant names

could be very tedious.

Fortunately, using SQL, your job could take less than a

minute.

In addition, you could format your output to read like a

sentence. You will find these SQL features very useful.

4



Tell Me / Show Me

DESCRIBE

Use the DESCRIBE (DESC) command to

display the structure of a table.

DESCRIBE <table_name>;

DESC returns the table name, table schema,

tablespace name, indexes, triggers, constraints,

and comments, as well as the data types,

primary and foreign keys, and which columns

can be nullable.

Table Name Type Length Precisio

n

Scal

e

Prima

ry

Key

Nullabl

e

Defau

lt

Comments

5



Tell Me / Show Me

DESCRIBE (continued)

DESC departments;

This is important information when inserting new rows into a

table because you must know the type of data each column will

accept and whether or not the column can be left empty.

Table Name Type Length Precision Scale Primary Key Nullable Default Comments

DEPAR

TMENT

S

DEPARTMENT

_ID

Number 4 0 1 Primary key column

of departments table.

DEPARTMENT

_NAME

Varchar2 30 A not null column that

shows name of a

department...

MANAGER_ID Number 6 0 √ Manager_id of a

department. Foreign

key to employee_id

column of employees

table...

LOCATION_ID Number 4 0 √ Location id where a

department is

located. Foreign key

to location_id column

of locations table.

6



Tell Me / Show Me

The Concatenation Operator

Concatenation means to connect or link together in a

series. The symbol for concatenation is 2 vertical bars

sometimes referred to as “pipes.” Columns on either side of

the || operator are combined to make a single output

column. The syntax is:

string1 || string2 || string_n

When values are concatenated, the resulting value is a

character string.

7



Tell Me / Show Me

The Concatenation Operator (continued)

In SQL, the concatenation operator can link columns to other

columns, arithmetic expressions, or constant values to create a

character expression. The concatenation operator is used to create

readable text output.

In the following example, the department_id is concatenated to the

department_name.

SELECT department_id || department_name

FROM departments;

DEPARTMENT_ID||DEPARTMENT_NAME

10Administration

20Marketing

50Shipping

60IT

…

8



Tell Me / Show Me

The Concatenation Operator (continued)

In this variation on the previous example, the || ' ' || is used to make

a space between the department_id and department_name. The

empty set of single quotation marks creates a space between the

column values.

SELECT department_id || ' ' ||department_name

FROM departments;

DEPARTMENT_ID||''||DEPARTMENT_NAME

10 Administration

20 Marketing

50 Shipping

60 IT

…

9



Tell Me / Show Me

Concatenation and Column Aliases

Column aliases are useful when using the

concatenation operator so that the column

heading does not appear as the default SELECT

line.

SELECT department_id || ' ' ||

department_name AS " Department

Info "

FROM departments;

SELECT first_name ||' ' ||

last_name AS "DJs on Demand

Clients"

FROM d_clients;

DJs on Demand Clients

Hiram Peters

Serena Jones

Lauren Vigil

Department Info

10 Administration

20 Marketing

50 Shipping

60 IT

…

10



Tell Me / Show Me

Concatenation and Literal Values

A literal value is a fixed data value such as a character, number, or

date. The following are examples of literal values:

• dollars

• has a monthly salary of:

• January 1, 2009

Using concatenation and literal values, you can create output that

looks almost like a sentence or statement.

Literal values can be included in the SELECT list with the

concatenation operator. Characters and dates must be enclosed in

a set of single quotes ' '. Every row returned from a query with

literal values will have the same character string in it.

11



Tell Me / Show Me

Concatenation and Literal Values (continued)

In the following example, King earns 24000 dollars a month. The strings, 'has a

monthly salary of' and 'dollars. ', are examples of literals. If you were to create a

SQL statement to produce output in this format, it would be written as:

SELECT last_name ||' has a monthly salary of ' || salary

|| ' dollars.' AS Pay

FROM employees;

Note the spacing after and before the single quotes. What happens if you

remove the spaces?

PAY

King has a monthly salary of 24000 dollars.

Kochhar has a monthly salary of 17000 dollars.

De Haan has a monthly salary of 17000 dollars.

Whalen has a monthly salary of 4400 dollars.

Higgins has a monthly salary of 12000 dollars.

Gietz has a monthly salary of 8300 dollars.

…

12



Tell Me / Show Me

Concatenation and Literal Values (continued)

You can also include numbers as literal values. In the following

example, the number 1 is concatenated to the strings, ' has a ' and '

year salary of '.

SELECT last_name ||

' has a ' || 1 ||

' year salary of ' ||

salary*12 || ' dollars.' AS Pay

FROM employees;

PAY

King has a 1 year salary of 288000 dollars.

Kochhar has a 1 year salary of 204000 dollars.

De Haan has a 1 year salary of 204000 dollars.

Whalen has a 1 year salary of 52800 dollars.

Higgins has a 1 year salary of 144000 dollars.

…

13



Tell Me / Show Me

Using DISTINCT to Eliminate Duplicate Rows

There are many times when you want to know

how many unique instances of something exist.

For example, what if you wanted a list of all of

the departments for which there are employees?

You could write a query to select the

department_ids from the employees table:

SELECT department_id

FROM employees;

Note all of the duplicate rows. How can you

modify the statement to eliminate the duplicate rows?

DEPARTMENT_ID

90

90

90

10

110

110

80

80

80

…

14



Tell Me / Show Me

Using DISTINCT to Eliminate Duplicate Rows (continued)

Unless you indicate otherwise, the output of a SQL query will display the

results without eliminating duplicate rows. In SQL, the DISTINCT keyword

is used to eliminate duplicate rows.

SELECT DISTINCT department_id

FROM employees;

The DISTINCT qualifier affects all listed columns and returns every distinct

combination of the columns in the SELECT clause. The keyword

DISTINCT must appear directly after the SELECT keyword.

DEPARTMENT_ID

90

20

110

80

50

10

60

15



Tell Me / Show Me

EXECUTE, SAVE, and EDIT

in Oracle Application Express

Now that you have been using Oracle Application Express to

create and execute statements, would it not be nice if you

could save those statements for later, so you could run them

again or perhaps edit them slightly and then save a new copy

of the statement?

Luckily for you, Oracle Application Express has facilities to

do just that. Your teacher will demonstrate these facilities for

you, and you can find further information in the Oracle

Application Express User Guide.

16



Summary



• Apply the concatenation operator to link columns to other

columns, arithmetic expressions, or constant values to

create a character expression

• Use column aliases to rename columns in the query result

• Enter literal values of type character, number, or date into a

SELECT statement

• Define and use DISTINCT to eliminate duplicate rows

• Edit, execute, and save SQL statements in Oracle

Application Express

17



Summary

Practice Guide




Limit Rows Selected

2

Limit Rows Selected


What Will I Learn?

Objectives


• Apply SQL syntax to restrict the rows returned from a

query

• Demonstrate application of the WHERE clause syntax

• Explain why it is important, from a business

perspective, to be able to easily limit data retrieved

from a table

• Construct and produce output using a SQL query

containing character strings and date values

3

Limit Rows Selected


Why Learn It?

Purpose

Have you ever had “information overload?”

The television is on, your Mom is asking you how school

went today, the phone rings, and the dog is barking.

Wouldn't it be nice to be able to restrict the amount of

information you have to process at one time? In SQL, this

is the job of the WHERE clause.

It is important to be able to choose the information you

need to see from a table. Tables can have millions of rows

of data, and it is a waste of resources to search and return

data you don't need or want.

4

Limit Rows Selected


Tell Me / Show Me

SELECT Statement

You use SELECT to retrieve information from the

database. A SELECT statement must include at a

minimum a SELECT clause and a FROM clause. The

WHERE clause is optional.

SELECT*|{[DISTINCT] column | expression alias]..}

FROM table

[WHERE condition(s)];

5

Limit Rows Selected


Tell Me / Show Me

WHERE Clause

When retrieving data from the database, you may need to

limit the rows of data that are displayed. You can

accomplish this using the WHERE clause. A WHERE

clause contains a condition that must be met, and it

directly follows the FROM clause in a SQL statement.

The syntax for the WHERE clause is:

WHERE column_name comparison_condition

column_names, constants or list of values

Note: An alias cannot be used in the WHERE clause!

6

Limit Rows Selected


Tell Me / Show Me

WHERE Clause (continued)

Examine the following SQL statement from the

DJs on Demand database: SELECT id, first_name, last_name

FROM d_partners;

Note how by adding a WHERE clause, the rows are limited to those

rows where the value of ID is 22.

SELECT first_name, last_name, expertise

FROM d_partners

WHERE id=22;

ID FIRST_

NAME

LAST_NAME

11 Jennifer cho

22 Jason Tsang

33 Allison Plumb

ID FIRST_

NAME

LAST_NAME

22 Jason Tsang

7

Limit Rows Selected


Tell Me / Show Me

Comparison Operators in the WHERE Clause

As you saw on the previous slide, the = sign can be used

in the WHERE clause. In addition to the equal to sign (=),

other comparison operators can be used to compare one

expression to a value or expression:

= equal to

> greater than

>= greater than or equal to

< less than

<= less than or equal to

<> not equal to (or != or ^=)

8

Limit Rows Selected


Tell Me / Show Me

Comparison Operators in the WHERE Clause (continued)

In the example below, which column name is used in the

WHERE clause? What comparison operator is used? Is "90"

a column name or a constant?

SELECT employee_id, last_name, department_id

FROM employees

WHERE department_id = 90 ;

9

Limit Rows Selected


Tell Me / Show Me

Character and Date Strings in the WHERE clause

Character strings and dates in the WHERE clause must be

enclosed in single quotation marks ' ' . But this does NOT

make them literal strings. They are still just character and

date strings.

Numbers, however, should not be enclosed in single

quotation marks.

Look at the following example from the DJs on Demand

database. The WHERE clause contains a string and is

enclosed in single quotation marks.

SELECT first_name, last_name

FROM d_clients

WHERE last_name = 'Jones';

10

Limit Rows Selected


Tell Me / Show Me

Character and Date Strings in the WHERE Clause

(continued)

What do you think will happen if the WHERE clause is written

as:

WHERE last_name = 'jones';

All character searches are case-sensitive. Because the

D_CLIENTS table stores all the last names in the proper case,

no rows are returned.

This is an important point to remember. In another lesson, you

will learn to use other SQL keywords UPPER, LOWER and

INITCAP that will make it easier to avoid a case-sensitive

mistake.

11

Limit Rows Selected


Tell Me / Show Me

Comparison Operators in the WHERE Clause

Comparison operators can be used in all of the following ways in

the WHERE clause:

WHERE event_date = '01-JAN-04'

WHERE rental_fee >=2000

WHERE cd_title = 'White Rose'

In the example shown from the DJs on Demand database, which

rows will be selected? Will salaries of 3000 be included in the

results set?

SELECT last_name, salary

FROM employees

WHERE salary <= 3000;

12

Limit Rows Selected


Summary



• Apply SQL syntax to restrict the rows returned from a

query

• Demonstrate application of the WHERE clause syntax

• Explain why it is important, from a business

perspective, to be able to easily limit data retrieved

from a table

• Construct and produce output using a SQL query

containing character strings and date values

13

Limit Rows Selected


Summary

Practice Guide




Comparison Operators

2



What Will I Learn?

Objectives


• Apply the proper comparison operator to return a

desired result

• Demonstrate proper use of BETWEEN, IN, and LIKE

conditions to return a desired result

• Distinguish between zero and the value of NULL as

unavailable, unassigned, unknown, or inapplicable

• Explain the use of comparison conditions and NULL

3



Why Learn It?

Purpose

We use comparisons in everyday conversation without really

thinking about it.

• "I can meet you BETWEEN 10:00 a.m. and 11:00 a.m."

• "I'm looking for a pair of jeans LIKE the ones you are wearing."

• "If I remember correctly, the best concert seats are IN rows

100, 200, and 300.“

The need to express these types of comparisons also exists in

SQL. Comparison conditions are used to find data in a table

meeting certain conditions. Being able to formulate a SELECT

clause to return specific data is a powerful feature of SQL.

4



Tell Me / Show Me


You are already familiar with the comparison operators such

as equal to (=), less than (<) and greater than (>). SQL has

other operators that add functionality for retrieving specific

sets of data. These include:

• BETWEEN…AND

• IN

• LIKE

5



Tell Me / Show Me

BETWEEN...AND

The BETWEEN...AND operator is used to select and

display rows based on a range of values. When used with

the WHERE clause, the BETWEEN...AND condition will

return a range of values between the specified lower and

upper limits and include both values.

6



Tell Me / Show Me

BETWEEN…AND (continued)

Note in the example from the DJs on Demand database the

values returned include the lower-limit value and the upper-

limit value. Values specified with the BETWEEN condition

are said to be inclusive. Note also that the lower-limit value

must be listed first.

SELECT title, year

FROM d_cds

WHERE year BETWEEN 1999 AND 2001;

Note that the output included the

lower-limit and upper-limit values.

TITLE YEAR

Party Music for All

Occasions

2000

Songs from My

Childhood

1999

Carpe Diem 2000

Here Comes the

Bride

2001

7



Tell Me / Show Me

BETWEEN…AND (continued)

Using BETWEEN...AND is the same as using the

following expression:

WHERE year >= 1999 AND year <= 2001

In fact, there is no performance benefit using

BETWEEN...AND or the alternate comparison operators.

We use BETWEEN...AND for simplicity in reading the

code and getting the results from the database.

8



Tell Me / Show Me

IN

The IN condition is also known as the "membership

condition." It is used to test whether a value is in a specified

set of values. For example, IN could be used to identify

students whose identification numbers are 2349, 7354 or

4333 or people whose international phone calling code is

1735, 82 or 10.

SELECT title, type_code

FROM d_songs

WHERE type_code IN (77,12);

TITLE TYPE_CODE

Its Finally Over 12

I’m Going to Miss My Teacher 12

Hurrah for Today 77

Let’s Celebrate 77

9



Tell Me / Show Me

IN (continued)

In this example, the WHERE clause could also be written

as a set of OR conditions:


FROM d_songs

WHERE type_code IN ( 77, 12 );

…

WHERE type_code = 77 OR type_code = 12;

As with BETWEEN...AND the IN condition can be written

using either syntax.

10



Tell Me / Show Me

LIKE

Have you ever gone shopping to look for something like

something you saw in a magazine or on television but you

weren't sure of the exact item? It's much the same with database

searches.

A manager may know that an employee's last name starts with

"S" but doesn't know the employee’s entire name. Fortunately, in

SQL, the LIKE condition allows you to select rows that match

either characters, dates or number patterns.

Two symbols -- the (%) and the underscore (_) -- called wildcard

characters, can be used to construct a search string.

11



Tell Me / Show Me

LIKE (continued)

The percent (%) symbol is used to represent any sequence of

zero or more characters. The underscore (_) symbol is used to

represent a single character.

In the example shown below, all employees with last names

beginning with any letter followed by an "o" and then followed by

any other number of letters will be returned.

SELECT last_name

FROM employees

WHERE last_name LIKE '_o%';

12



Tell Me / Show Me

LIKE (continued)

SELECT last_name

FROM employees

WHERE last_name LIKE '_o%';

Which of the following last names could have been

returned from the above query?

1. Sommersmith

2. Oog

3. Fong

4. Mo

If you said 1, 2, 3 and 4 you are correct!

13



Tell Me / Show Me

LIKE (continued)

One additional option that is important: When you need to have

an exact match for a string that has a % or _ character in it, you

will need to indicate that the % or the _ is not a wildcard but is

part of the item you're searching for. The ESCAPE option

backward slash (\) is used to indicate that the underscore or %

is part of the name, not a wildcard value.

For example, if the database had stored CD track numbers as

TRA_6, the WHERE clause would need to be written as:

WHERE track LIKE 'TRA\_%'

14



Tell Me / Show Me

IS NULL, IS NOT NULL

Remember NULL? It is the value that is unavailable, unassigned,

unknown, or inapplicable. Being able to test for unavailable,

unassigned, or unknown is often desirable. You may want to

know all the dates in June that, right now, do not have a concert

scheduled. You may want to know all of the clients who do not

have phone numbers recorded in your database.

The IS NULL condition tests for unavailable, unassigned, or

unknown data. IS NOT NULL tests for data that is present in the

database. In the example on the next slide, the WHERE clause is

written to retrieve all the last names and manager IDs of those

employees who do not have a manager.

15



Tell Me / Show Me

IS NULL, IS NOT NULL (continued)

SELECT last_name, manager_id

FROM employees

WHERE manager_id IS NULL;

Read the following and explain what you

expect will be returned:

SELECT first_name,

last_name,auth_expense_amt

FROM d_partners

WHERE auth_expense_amt IS NULL;

16



Summary



• Apply the proper comparison operator to return a

desired result

• Demonstrate proper use of BETWEEN, IN, and LIKE

conditions to return a desired result

• Distinguish between zero and the value of NULL as

unavailable, unassigned, unknown, or inapplicable

• Explain the use of comparison conditions and NULL

17



Summary

Practice Guide





INSTRUCTOR NOTES SECTION 16 – Working with Columns, Characters and Rows Lesson Slide 1: Working with Columns, Characters and Rows Lesson Preparation Any time students have extra time in class, have them work on the Self Test software Practice Test Learning Mode questions. Select the question set appropriate for the objectives currently being studied. For example, the first set of questions assess “Writing Basic SQL Select Statements.” The Self Test questions can be challenging, but are designed to test understanding of basic concepts, not simply SQL facts. What to Watch For As the SQL syntax becomes more complicated, make sure students understand each concept. To monitor student progress in completing the practice exercises, you can:

• Randomly choose three or four questions and ask students to copy the SQL statement into Notepad, print it, and turn it in for grading.

• Use the teacher access to each student's schema in Oracle Application Express. Ask students to save three or four practices as “Practice Section X, Lesson Y” in the Archive section. Review the query examples in each student's saved Archive.

• Ask one or two students to write the answers to selected questions on the board. Take time for students to review all the tables used in the DJ on Demand, Global Fast Foods, and Oracle databases. Developing a mental picture of the tables will help them be better able to formulate more difficult queries in the future. Slide 2: What Will I Learn? Read the objectives. Pronounce “concatenation” – kon-kat-uh-NAY-shuhn – the state of being linked together as in a chain; union in a linked series. Slide 3: Why Learn It? If time permits ask students to find tables from original sources such as the newspaper or Internet. Show the tables to the class and have students verbally construct SELECT statements from them. Make it a game. Give two examples they can use with their class and leave them in this section. See www.wri.org/facts/data-tables.html for all kinds of tables that could make good practice with “real” data.



Instructor Resource Guide Slide 4: Tell Me / Show Me – DESCRIBE Before beginning this lesson, use a simple SQL statement to demonstrate how to edit, execute, and save SQL statements to files in Oracle Application Express. SQL statements are saved in the Archive file and can be accessed from clicking the SQL tab in the menu bar and then clicking the Archive tab. Slide 5: Tell Me / Show Me – DESCRIBE (continued) Explain DESCRIBE or DESC and have students use Oracle Application Express to describe a table in any database. Show students where the pipe (|) character is on their keyboard. Make up sentences that students must display using the concatenation operator. Demonstrate that leaving a space after or before the single quotation mark also creates a space between words. Point out that an alias will eliminate the SELECT line appearing as the column heading. Run the example twice, the second time with an alias called Event to show the difference. Using the DJ on Demand EVENT table, create and display: “On date, the event was name” Answer: SELECT 'On ' ||event_date || ' the event was ' ||name FROM d_events Slide 6: Tell Me / Show Me – CONCATENATION Demonstrate several errors to show students how to read the error statements. This will help eliminate the “mine doesn't work” frustration. Spell SELECT as SELCT. Omit FROM. In FROM use a column name instead of a table name. SELECT a table that does not exist in the database. Misspell a column name. Fail to leave a space after SELECT and the column name. SELECT several columns but omit the comma between column names. Slide 7: Tell Me / Show Me – CONCATENATION & COLUMN ALIASES No instructor notes for this slide Slide 8: Tell Me / Show Me – CONCATENATION & COLUMN ALIASES (continued) No instructor notes for this slide Slide 9: Tell Me / Show Me – CONCATENATION & COLUMN ALIASES (continued) No instructor notes for this slide



Instructor Resource Guide Slide 10: Tell Me / Show Me – CONCATENATION & COLUMN ALIASES (continued) No instructor notes for this slide Slide 11: Tell Me / Show Me – CONCATENATION & COLUMN ALIASES (continued) Remind students that numbers do not have to be enclosed in single quotes. Slide 12: Tell Me / Show Me – DISTINCT No instructor notes for this slide Slide 13: Tell Me / Show Me – DISTINCT (continued) Discuss the graphic and identify the number of DISTINCT colors there are. Slide 14: Tell Me / Show Me – DISTINCT (continued) In the band_logo and color example, ask students to list all the different combinations there are with logos and colors: six different distinct combinations (2 bands * 3 shirt colors). Students will not be able to execute the band_logo and color query. Slide 15: Tell Me / Show Me – EXECUTE, SAVE AND EDIT STATEMENTS IN OAE No instructor notes for this slide Slide 16: Summary – In this lesson you have learned about: No instructor notes for this slide Slide 17: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 16 – Limit Rows Selected Lesson Slide 1: Limit Rows Selected What to Watch For Adding the WHERE clause is the first step in beginning to build more complicated SELECT statements. It is critical that students understand how to construct a basic SELECT statement at this point. Connections Give students or ask students for other examples where we “restrict” data in our everyday lives. When you go shopping, do you go to a store planning to buy one of everything in that store? No, you select certain items to buy. Your sales receipt will list the selection of items you purchased, not all the items in the store. Why do grocery stores put signs above the aisles? (Possible answer: so you can limit your search) Why are similar items in the grocery store shelved together? Imagine having all items in the grocery store placed on any shelf in any location. Isn't it easier to select the beverage aisle and see all the sodas in one place? Did the signs help limit our search? Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me –SELECT Statement Review the SELECT clause general syntax. The [ ] mean this is optional. The | means “or.” Slide 5: Tell Me / Show Me – WHERE Clause No instructor notes for this slide Slide 6: Tell Me / Show Me – WHERE Clause (continued) What is the column name used in the WHERE clause? department_id What comparison operator is used? = Is “90” a column name or a constant? constant or data value Slide 7: Tell Me / Show Me – Comparison Operators in the WHERE Clause What is the column name used in the WHERE clause? department_id What comparison operator is used? = Is “90” a column name or a constant? constant or data value Slide 8: Tell Me / Show Me – Comparison Operators in the WHERE Clause (continued) No instructor notes for this slide



Instructor Resource Guide Slide 9: Tell Me / Show Me – Character and Date Strings in the WHERE Clause (continued) No instructor notes for this slide Slide 10: Tell Me / Show Me – Character and Date Strings in the WHERE Clause (continued) No instructor notes for this slide Slide 11: Tell Me / Show Me – Comparison Operators in the WHERE clause In the example, explain that < = means 3000 will be selected. Give other examples with >= and <>. Slide 12: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 13: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 16 – Comparison Operators Lesson Slide 1: Comparison Operators Lesson Preparation Ask students to find examples in the newspaper, online, or in another textbook that use the BETWEEN...AND or LIKE conditions. Rewrite the sentence using SQL syntax. For example, in this excerpt from a poem by Carl Sandburg called “Prairie,” you could say... “Here between the sheds of the Rocky Mountains and the Appalachians, here now a morning star fixes a fire sign over the timber claims and cow pastures, the corn belt, the cotton belt, the cattle ranches....” WHERE prairie BETWEEN the sheds of the Rocky Mountains AND the Appalachians Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – COMPARISON OPERATORS In the syntax introduced in this lesson, the WHERE clause has become more complex. Explain to students that the WHERE clause can be used to select for combinations of values. For example, “I would like to know Global Fast Foods employees whose manager ID is 19 and earn a salary less than $12.00 per hour. SELECT * FROM f_staffs WHERE manager_id = 19 and salary <12.00; Slide 5: Tell Me / Show Me – BETWEEN…AND Note that the year column is defined as a VARCHAR2 datatype. Because of this, the SQL statement could have been written without quotes around the year values: SELECT title, year FROM d_cds WHERE year BETWEEN 1999 AND 2001; The reason for this is because when Oracle compares a numeric literal (i.e., 1999) against a VARCHAR2 column, Oracle implicitly converts the data into a character (VARCHAR2) datatype. But it will slow down the execution of the statement slightly, so it is best to be as accurate as possible when writing SQL statements. Check to make sure students understand the term “inclusive” when used with BETWEEN...AND.



Instructor Resource Guide Slide 6: Tell Me / Show Me – BETWEEN…AND (continued) No instructor notes for this slide Slide 7: Tell Me / Show Me – BETWEEN…AND (continued) No instructor notes for this slide Slide 8: Tell Me / Show Me – IN Explain “membership condition” to students and ask them to give an example. Possible responses: The membership condition for being IN this year's graduating class is that you must have completed all course credit requirements. Slide 9: Tell Me / Show Me – IN (continued) No instructor notes for this slide Slide 10: Tell Me / Show Me – LIKE No instructor notes for this slide Slide 11: Tell Me / Show Me – LIKE (continued) No instructor notes for this slide Slide 12: Tell Me / Show Me – LIKE (continued) No instructor notes for this slide Slide 13: Tell Me / Show Me – LIKE (continued) Review the BETWEEN...AND, IN, and LIKE conditions. As each syntax is introduced, have students generate examples for class practice. For example, “from the DJs on Demand database give me all producers where the producer begins with T. SELECT producer FROM d_cds WHERE producer LIKE 'T%'; Slide 14: Tell Me / Show Me – IS NULL, IS NOT NULL Discuss the concept of NULL and the difference between values that are unknown, values that are unknowable, and values that are inapplicable. Where does the sky end? Is it unknown, unknowable, or inapplicable? Slide 15: Tell Me / Show Me – IS NULL, IS NOT NULL (continued) Discuss the concept of NULL and the difference between values that are unknown, values that are unknowable, and values that are inapplicable. Expected result will be three columns where the auth_expense_amt column is null. Ask your students to tell you if the following expression is true or false: x > y. And only tell them that x=5. As long as y is unknown they cannot possibly answer that question.



Instructor Resource Guide Slide 16: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 17: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide PRACTICE SOLUTIONS SECTION 16 – Working with Columns, Characters and Rows Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. DISTINCT A command that suppresses duplicates

Concatenation Links two columns together to form one character

data column

String A group of character data

DESCRIBE (DESC) An SQL plus command that displays the structure of a table

Try It / Solve It 1. The manager of Global Fast Foods would like to send out coupons for the upcoming

sale. He wants to send one coupon to each household. Create the SELECT statement that returns the customer last name and a mailing address.

Solution: SELECT DISTINCT last_name, address,city, state, zip FROM f_customers;

2. Each statement below has errors. Correct the errors and execute the query in Oracle

Application Express.

a. SELECT first name FROM f_staffs;

b.

SELECT first_name |" " | last_name AS "DJs on Demand Clients" FROM d_clients;

c.

SELECT DISCTINCT f_order_lines FROM quantity;




d. SELECT order number FROM f_orders;

Solution: a. Missing underscore first_name b. Incorrect single bar concatenation operator and double quotation marks c. DISTINCT incorrectly spelled and column and table names in wrong place d. Missing underscore order_number

3. Sue, Bob, and Monique were the employees of the month. Using the f_staffs table,

create a SELECT statement to display the results as shown in the Super Star chart.

Super Star *** Sue *** Sue *** *** Bob *** Bob *** *** Monique *** Monique ***

Solution: SELECT '***'||first_name ||'***'||first_name||'***' AS "Super Star" FROM f_staffs;

4. Which of the following is TRUE about the following query?

SELECT first_name, DISTINCT birthdate FROM f_staffs;

a. Only two rows will be returned. b. Four rows will be returned. c. Only Fred 05-JAN-88 and Lizzie 10-NOV-87 will be returned. d. No rows will be returned.

Solution: d. No rows will be returned. DISTINCT must appear directly after SELECT.



Instructor Resource Guide 5. Global Fast Foods has decided to give all staff members a 5% raise. Prepare a report

that presents the output as shown in the chart. EMPLOYEE LAST NAME CURRENT SALARY SALARY WITH 5% RAISE

Solution: SELECT last_name AS "EMPLOYEE LAST NAME", salary AS "CURRENT SALARY",salary * 1.05 AS "SALARY WITH 5% RAISE" FROM f_staffs ;

6. Create a query that will return the structure of the Oracle database EMPLOYEES

table. Which columns are marked “nullable”? What does this mean?

Solution: DESCRIBE employees; FIRST_NAME, PHONE_NUMBER, SALARY, COMMISSION_PCT, MANAGER_ID, DEPARTMENT_ID Nullable means that when data is entered into those columns, they can have NO VALUE. Null is not 0, or a space, but an unknowable value.

7. The owners of DJs on Demand would like a report of all items in their D_CDs table

with the following column headings: Inventory Item, CD Title, Music Producer, and Year Purchased. Prepare this report.

Solution: SELECT cd_number AS "Inventory Item", title AS "CD Title", producer AS "Music Producer", year AS "Year Purchased" FROM d_cds ;

8. True/False – The following SELECT statement executes successfully:

SELECT last_name, job_id, salary AS Sal FROM employees;

Solution: True

9. True/False – The following SELECT statement executes successfully:

SELECT * FROM job_grades;

Solution: True



Instructor Resource Guide 10. There are four coding errors in this statement. Can you identify them? SELECT employee_id, last_name

sal x 12 ANNUAL SALARY FROM employees;

Solution: Missing comma after last_name, sal*12 and "ANNUAL SALARY", sal should be salary

11. In the arithmetic expression salary*12 - 400, which operation will be evaluated first?

Solution: Salary * 12 12. Which of the following can be used in the SELECT statement to return all columns of

data in the Global Fast Foods f_staffs table? a. column names b. * c. DISTINCT id d. both a and b

Solution: d.

13. Using SQL to choose the columns in a table uses which capability?

a. selection b. projection c. partitioning d. join

Solution: b. projection

14. SELECT department_id, first_name, last_name AS "Employee". The column heading

in the query result will appear as: a. EMPLOYEE b. employee c. Employee d. "Employee:

Solution: c. Employee



Instructor Resource Guide 15. Which expression below will produce the largest value?

a. SELECT salary*6 + 100 b. SELECT salary* (6 + 100) c. SELECT 6(salary+ 100) d. SELECT salary+6*100

Solution: b. SELECT salary* (6 + 100)

16. Which statement below will return a list of employees in the following format?

Mr./Ms. Steven King is an employee of our company.

a. SELECT "Mr./Ms."||first_name||' '||last_name 'is an employee of our company.' AS "Employees"

FROM employees; b. SELECT 'Mr./Ms. 'first_name,last_name ||' '||'is an employee of our company.' FROM employees;

c. SELECT 'Mr./Ms. '||first_name||' '||last_name ||' '||'is an employee of our company.' AS "Employees"

FROM employees ; d. SELECT Mr./Ms. ||first_name||' '||last_name ||' '||"is an employee of our company."

AS "Employees" FROM employees

Solution: c. SELECT 'Mr./Ms. '||first_name||' '||last_name ||' '||'is an employee of our company.' AS "Employees" FROM employees ;

17. Which is true about SQL statements?

a. SQL statements are case-sensitive b. SQL clauses should not be written on separate lines. c. Keywords cannot be abbreviated or split across lines. d. SQL keywords are typically entered in lowercase; all other words in uppercase.

Solution: c. Keywords cannot be abbreviated or split across lines.



Instructor Resource Guide 18. Which queries will return three columns each with UPPERCASE column headings?

a. SELECT "Department_id", "Last_name", "First_name" FROM employees;

b. SELECT DEPARTMENT_ID, LAST_NAME, FIRST_NAME FROM employees;

c. SELECT department_id, last_name, first_name AS UPPER CASE FROM employees

d. SELECT department_id, last_name, first_name FROM employees;

Solution: b. SELECT DEPARTMENT_ID, LAST_NAME, FIRST_NAME FROM employees; d. SELECT department_id, last_name, first_name FROM employees;

19. Which statement below will likely fail? a. SELCT * FROM employees; b. Select * FROM employees; c. SELECT * FROM EMPLOYEES; d. SelecT* FROM employees;

Solution: a. SELCT * FROM employees;

20. Click on the History link at the bottom of the SQL Commands window. Scroll or use

the arrows at the bottom of the page to find the statement you wrote to solve problem 3 above. (The one with the column heading SuperStar). Click on the statement to load it back into the command window. Execute the command again, just to make sure it is the correct one that works. Once you know it works, click on the SAVE button in the top right corner of the SQL Commands window, and enter a name for your saved statement. Use your own initials and “_superstar.sql”, so if your initials are CT then the filename will be CT_superstar.sql.

Log out of OAE, and log in again immediately. Navigate back to the SQL Commands

window, click the Saved SQL link at the bottom of the page and load your saved SQL statement into the Edit window. This is done by clicking on the script name. Edit the statement, to make it display + instead of *. Run your amended statement and save it as initials_superplus.sql.



Instructor Resource Guide SECTION 16 – Limit Rows Selected Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. WHERE clause Restricts the rows returned by a select statement

Comparison conditions Compares one expression to another value or

expression

Try It / Solve It 1. Using the Global Fast Foods database, retrieve the customer’s first name, last name,

and address for the customer who uses ID 456.

Solution: SELECT first_name, last_name, address FROM f_customers WHERE Id = 456;

2. Show the name, start date, and end date for Global Fast Foods' promotional item

“ballpen and highlighter” giveaway.

Solution: SELECT name, start_date, end_date, give_away FROM f_promotional_menus WHERE give_away = 'ballpen and highlighter';

3. Create a SQL statement that produces the following output:

Oldest The 1997 recording in our database is The Celebrants Live in Concert

Solution: SELECT 'The 1997 recording in our database is ' ||title AS "Oldest" FROM d_cds WHERE year = 1997;



Instructor Resource Guide 4. The following query was supposed to return the CD title "Carpe Diem" but no rows

were returned. Correct the mistake in the statement and show the output. SELECT produce, title FROM d_cds WHERE title = 'carpe diem' ;

Solution: SELECT producer, title FROM d_cds WHERE title = 'Carpe Diem';

5. The manager of DJ on Demand would like a report of all the CD titles and years of

CDs that were produced before 2000.

Solution: SELECT title, year FROM d_cds WHERE year < 2000;

6. Which values will be selected in the following query?

SELECT salary FROM employees WHERE salary < = 5000; a. 5000 b. 0 - 4999 c. 2500 d. 5

Solution: All will be selected



Instructor Resource Guide For the next three questions, use the following table information: TABLE NAME: students COLUMNS: studentno NUMBER(6) fname VARCHAR2(12) lname VARCHAR(20) sex CHAR(1) major VARCHAR2(24) 7. Write a SQL statement that will display the student number (studentno), first name

(fname), and last name (lname) for all students who are female (F) in the table named students.

Solution: SELECT student_id, fname, lname From students where sex = 'F';

8. Write a SQL statement that will display the student number (studentno) of any

student who has a PE major in the table named students. Title the studentno column Student Number.

Solution: SELECT studentno AS "Student Number" (AS is optional) FROM students WHERE major = 'PE' ;

9. Write a SQL statement that lists all information about all male students in the table

named students.

Solution: SELECT * FROM students WHERE sex = 'M';

10. Write a SQL statement that will list the titles and years of all the DJs on Demand's

CDs that were not produced in 2000.

Solution: SELECT title, year FROM d_cds WHERE year != 2000 ; (or ^= or <> );



Instructor Resource Guide 11. Write a SQL statement that lists the Global Fast Foods employees who were born

before 1980.

Solution: SELECT first_name, last_name FROM f_staffs WHERE birthdate < '01-JAN-80';



Instructor Resource Guide SECTION 16 – Comparison Operators Lesson Vocabulary ESCAPE This option identifies that the escape characters

should be interpreted literally

IS NULL Condition tests for null values

BETWEEN Displays rows based on a range of values

Inclusive Including the specified limits and the area between them; the numbers 1-10, inclusive

LIKE Selects rows that match a character pattern

IN Tests for values in a specified list of values

Try It / Solve It 1. Display the first name, last name, and salary of all Global Fast Foods staff whose

salary is between $5.00 and $10.00 per hour.

Solution: SELECT first_name, last_name, salary FROM f_staffs WHERE salary BETWEEN 5.00 and 10.00;

2. Display the location type and comments for all DJs on Demand venues that are

Private Home.

Solution: SELECT loc_type, comments FROM d_venues WHERE loc_type = 'Private Home';



Instructor Resource Guide 3. Using only the less than, equal, or greater than operators, rewrite the following query:

SELECT first_name, last_name FROM f_staffs WHERE salary BETWEEN 20.00 and 60.00;

Solution: SELECT first_name, last_name FROM f_staffs WHERE salary >= 20 and salary <=60;

4. Create a list of all the DJs on Demand CD titles that have “a” as the second letter in

the title.

Solution: SELECT title FROM d_cds WHERE title LIKE '_a%';

5. Who are the partners of DJs on Demand who do not get an authorized expense

amount?

Solution: SELECT first_name, last_name FROM d_partners WHERE auth_expense_amt IS NULL;

6. Select all the Oracle database employees whose last names end with “s” Change the

heading of the column to read Possible Candidates.

Solution: SELECT last_name AS "Possible Candidates" FROM employees WHERE last_name LIKE '%s';



Instructor Resource Guide 7. Which statement(s) are valid?

a. WHERE quantity <> NULL; b. WHERE quantity = NULL; c. WHERE quantity IS NULL; d. WHERE quantity != NULL;

Solution: c. WHERE quantity IS NULL;

8. Write a SQL statement that lists the songs in the DJs on Demand inventory that are

type code 77, 12 or 1.

Solution: SELECT title FROM d_songs WHERE type_code IN ( 77,12,1);



Logical Comparisons

and Precedence Rules

2

Logical Comparisons and Precedence Rules


What Will I Learn?

Objectives


• Evaluate logical comparisons to restrict the rows

returned based on two or more conditions

• Apply the rules of precedence to determine the order

in which expressions are evaluated and calculated

3



Why Learn It?

Purpose

Not too many things in life depend on

just one condition.

For instance, if you want to go to college,

you probably need good grades and the

tuition money to pay for it.

If you have extra money, you could either

save it or spend it.

If you want to go to a movie, you may not

want to go this weekend and you may

not want to sit in the first 10 rows of the

theater.

sdm_s18_l01_a01

4



Why Learn It?

Purpose (continued)

In SQL, it is often desirable to be able to restrict the rows

returned by a query based on two or more conditions.

As the business manager of Global Fast Foods, you may

need to know the names of your staff who are either cooks or

order takers. You don't need or want the entire staff list, you

just want a subset of it.

Conditional operators such as AND, NOT and OR make

these types of requests easy to do.

5



Tell Me / Show Me

Logical Conditions

Logical conditions combine the result of

two component conditions to produce a

single result based on them. For example,

to attend a rock concert, you need to buy

a ticket AND have transportation to get

there. If both conditions are met, you can

go to the concert.

What if you can't get transportation, can

you go?sdm_s18_l01_a02

6



Tell Me / Show Me

Logical Conditions (continued)

Another logical condition combines two

component conditions with OR. All employees

will receive a raise either by having a perfect

attendance record OR by meeting their monthly

sales quota. If an employee meets either of

these two conditions, he/she gets a raise. Using

syntax you already know, rewrite the code to

produce the same results.

…WHERE cd_id NOT IN (105, 206, 332);

Will a query using this WHERE clause select

cd_id = 206? The NOT operator excludes the

condition from the query result.

7



Tell Me / Show Me

Logical Operators

A logical operator combines the results of two or more

conditions to produce a single result. A row is returned

ONLY IF the overall result of the condition is true.

AND -- Returns TRUE if both conditions are true.

OR -- Returns TRUE if either condition is true.

NOT -- Returns TRUE if the condition is false.

8



Tell Me / Show Me

AND Operator

In the query below, the results returned will

be rows that satisfy BOTH conditions

specified in the WHERE clause.

SELECT id, title, duration,

type_code

FROM d_songs

WHERE id > 40

AND type_code = 77;

ID TITLE DURATION TYPE_CODE

47 Hurrah for Today 3 min 77

49 Let’s Celebrate 8 min 77

sdm_s18_l01_a03

9



Tell Me / Show Me

OR Operator

If the WHERE clause uses the OR condition, the results

returned from a query will be rows that satisfy either one of

the OR conditions. In other words, all rows returned have

an ID greater than 48 OR they have a type_code equal to

77. Look at the row with “Let’s Celebrate” -- it has both!

SELECT id, title, duration, type_code

FROM d_songs

WHERE id > 48

OR type_code = 77; ID TITLE DURATION TYPE_CODE

47 Hurray for Today 3 min 77

49 Let’s Celebrate 8 min 77

50 All These Years 10 min 88

10



Tell Me / Show Me

NOT Operator

The NOT operator will return rows that do

NOT satisfy the condition in the WHERE

clause.


FROM d_songs

WHERE type_code NOT IN 77;

TITLE TYPE_CODE

It’s Finally Over 12

I’m Going to Miss My Teacher 12

Meet Me At the Altar 1

All These Years 88

11



Tell Me / Show Me

Rules of Precedence or What Happens First?

Consider the following SELECT statement. In what

order are the expressions evaluated and

calculated?

SELECT last_name||' '||salary*1.05

As "Employee Raise"

FROM employees

WHERE department_id IN(50,80)

AND first_name LIKE 'C%'

OR last_name LIKE '%s%';

Luckily, when things get this complicated, SQL has

a few basic rules that are easy to follow.

12



Tell Me / Show Me

Rules of Precedence or What Happens

First? (continued)

Notice that the AND operator is evaluated

before the OR operator.

ORDER OPERATORS

1 Arithmetic + - * /

2 Concatenation ||

3 Comparison <, <=, >, >=, <>

4 IS (NOT) NULL, LIKE, (NOT)

IN

5 (NOT) BETWEEN

6 NOT

7 AND

8 OR

This means that if either of

the conditions in the AND

statement are not met, then

the OR operator is used to

select the rows.

This is an important concept

to remember.

13



Tell Me / Show Me


(Continued)

Review the next two examples. What will be the output of

each query shown? Is the output what you predicted?

SELECT last_name, specialty, auth_expense_amt

FROM d_partners

WHERE specialty ='All Types'

OR specialty IS NULL

AND auth_expense_amt = 300000;

The order of operations is:

1. Specialty IS NULL AND

auth_expense_amt =

300000. Both these

conditions must be met to

be returned.

2. Any instance of specialty

= 'All Types' will be

returned.

14



Tell Me / Show Me


(Continued)

SELECT last_name, specialty, auth_expense_amt

FROM d_partners

WHERE (specialty ='All Types'

OR specialty IS NULL)

AND auth_expense_amt = 300000;

The order of operations is:

1. The values in the

parentheses are selected.

2. All instances of the

values in the parentheses

that also match

auth_expense_amt =

300000 will be returned.

15



Summary



• Evaluate logical comparisons to restrict

the rows returned based on two or more

conditions

• Apply the rules of precedence to

determine the order in which

expressions are evaluated and

calculated

16



Summary

Practice Guide




Sorting Rows

2

Sorting Rows


What Will I Learn?

Objectives


• Construct a query to sort a results set in ascending

or descending order

• State the order in which expressions are evaluated

and calculated based on the rules of precedence

• Construct a query to order a results set using a

column alias

• Construct a query to order a results set for single or

multiple columns

3

Sorting Rows


Why Learn It?

Purpose

By nature, most of us need order in our lives. Imagine if each

time you had dinner, you had to look in every kitchen drawer

or cabinet to find a knife and a fork? Ordering, grouping, and

sorting makes finding things easier.

Biologists group animals in phyla, astronomers order

brightness of stars by magnitude, and programmers organize

Java code in classes. For database design, business

functions are ordered by entities and attributes; in database

information, SQL uses the ORDER BY clause.

Being able to sort results is a convenient feature in SQL and

enables programmers to display information in many different

ways.

4

Sorting Rows


Tell Me / Show Me

ORDER BY Clause

Information sorted in ascending order is familiar to most

of us. It's what makes looking up a number in a phone

book, finding a word in the dictionary, or locating a house

by its street address relatively easy.

SQL uses the ORDER BY clause following the FROM

clause to order data. The ORDER BY clause can specify

several ways in which to order rows returned in a query.

5

Sorting Rows


Tell Me / Show Me

ORDER BY Clause (continued)

The following DJs on Demand example uses

the ORDER BY clause to order the years in

ascending (default) order. Note: The ORDER

BY clause must be the last clause of the SQL

statement.

SELECT title, year

FROM d_cds

ORDER BY year;

TITLE YEAR

The Celebrants Live in Concert 1997

Graduation Songbook 1998

Songs from My Childhood 1999

Carpe Diem 2000

Party Music for All Occasions 2000

Here Comes the Bride 2001

Back to the Shire 2002

Whirled Peas 2004

6

Sorting Rows


Tell Me / Show Me

ORDER BY Clause (continued)

• The default sort order is ascending.

• Numeric values are displayed lowest to highest.

• Date values are displayed with the earliest value

first.

• Character values are displayed in alphabetical order.

• Null values are displayed last in ascending order and

first in descending order.

7

Sorting Rows


Tell Me / Show Me

Sorting in Descending Order

You can reverse the default order in the ORDER BY

clause to descending order by specifying the DESC

keyword after the column name in the ORDER BY

clause.

SELECT title, year

FROM d_cds

ORDER BY year DESC;

TITLE YEAR

Whirled Peas 2004




Carpe Diem 2000




How would you order the

following dates in

descending order? 22-

MAY-85, null, 10-JAN-04,

17-NOV-55, 21-DEC-98

8

Sorting Rows


Tell Me / Show Me

TITLE RECORDING

DATE

The Celebrants Live in

Concert

1997



Carpe Diem 2000




Whirled Peas 2004

Using Column Aliases

You can order data by using a column alias.

The alias used in the SELECT statement is

added to the ORDER BY clause.

SELECT title, year AS

"Recording Date"

FROM d_cds

ORDER BY "Recording Date";

9

Sorting Rows


Tell Me / Show Me

Sorting With Other Columns

It is also possible to use the ORDER BY

clause to order output by a column that

is not listed in the SELECT clause. In

the following example, the data is sorted

by the last_name column even though

this column is not listed in the SELECT

statement.

SELECT employee_id,

first_name

FROM employees

WHERE employee_id < 105

ORDER BY last_name;

EMPLOYEE_ID FIRST_NAME

102 Lex

104 Bruce

103 Alexander

100 Steven

101 Neena

10

Sorting Rows


Tell Me / Show Me

Order of Execution

The order of execution of a SELECT statement is as

follows:

1. FROM clause: locates the table that contains the data

2. WHERE clause: restricts the rows to be returned

3. SELECT clause: selects from the reduced data set the

columns requested

4. ORDER BY: orders the results set

11

Sorting Rows


Tell Me / Show Me

Sorting results by more than one

column is like first sorting all the

students in the school by class or

grade level and then within each

grade-level group, sorting

students alphabetically by last

name.

SELECT title, year

FROM d_cds

ORDER BY title, year;

TITLE YEAR


Carpe Diem 2000






Whirled Peas 2004

Sorting With Multiple Columns

It is also possible to sort query results by more than one

column. In fact, there is no limit on how many columns you can

add to the ORDER BY clause.

12

Sorting Rows


Tell Me / Show Me

Sorting With Multiple Columns (continued)

To create an ORDER BY clause to sort by

multiple columns, specify the columns to be

returned and separate the column names

using commas. If after listing the columns you

want to reverse the order of a column, add

DESC after its name.

SELECT title, year

FROM d_cds

ORDER BY year DESC,title;

TITLE YEAR





Carpe Diem 2000



13

Sorting Rows


Summary



• Construct a query to sort a results set in ascending

or descending order

• State the order in which expressions are evaluated

and calculated based on the rules of precedence

• Construct a query to order a results set using a

column alias

• Construct a query to order a results set for single or

multiple columns

14

Sorting Rows


Summary

Practice Guide




Introduction to Functions – Single Row

Functions

2

Introduction to Functions – Single Row Functions


What Will I Learn?

Objectives


• Identify appropriate applications of single-row

functions in query statements

• Classify a function as a single-row or multi-row

function

• Differentiate between single-row functions and multi-

row functions and the results returned by each

3



Why Learn It?

Purpose

When you put money in a drink

machine, something happens between

the time the money is deposited and

your favorite drink is dispensed. The

transaction is processed internally by

the machine. Your money is the input

and the drink is the output. The

machine performs a function. The

machine:

• Counts your money

• Makes sure your selection is

chosen

• Returns change, if necessary

sdm_s18_l05_a01

4



Why Learn It?

sdm_s18_l05_a02

Purpose (continued)

In SQL, there are many types of

functions that are used to transform

input in one form to output in

another form. These functions are

used to manipulate data values.

How could you find out whether the

information in the DJs on Demand

CD titles table is stored in

uppercase or lowercase? Execute

a SELECT statement to look at the

output.

SELECT title

FROM d_cds;

5



Tell Me / Show Me

Functions

Functions are programs that do an action on a value or

column and produce something different as output.

Functions have both input and output. Input into a

function is referred to as an argument.

In the drink machine example, the input is money and

the output is a drink.

FunctionInput(Argument)

Output

Drink MachineMoney Drink

6



Tell Me / Show Me

Functions

Single-row

functions

Multiple-row

functions

Functions (continued)

Oracle has two distinct types of functions:

• Single-Row

• Multiple-Row

7



Tell Me / Show Me

Single-Row Versus Multiple-Row Functions

Single-Row Functions

These functions operate on single rows only and return one result

per row. There are different types of single-row functions including

character, number, date, and conversion functions.

Multiple-Row Functions

Functions can manipulate groups of rows to give one result per

group of rows. These functions are known as group functions.

Single-row

functions

Multiple-row

functions

8



Tell Me / Show Me


In SQL, functions are a very

powerful feature. They can be

used to:

• Perform calculations

such as rounding

numbers to a specified

decimal place

• Modify individual data

items such as converting

character values from

uppercase to lowercase

• Manipulate output for

groups of rows by finding

an average or sum for

several rows

CHARACTER

GENERAL NUMBER

SINGLE-ROW

FUNCTIONS

CONVERSION DATE

9



Tell Me / Show Me


(continued)

• Format dates and

numbers for display such

as converting the internal

numeric database date

format to a standard

format

• Convert column data

types such as converting

a character string to a

number or date

CHARACTER

GENERAL NUMBER

SINGLE-ROW

FUNCTIONS

CONVERSION DATE

10



Tell Me / Show Me

Single-Row Functions (continued)

Single-Row Functions accept one or more arguments and will

return a single result per row. So if you apply the single row

function to 12 rows, you will get 12 results out of the single row

function.

In summary, single-row functions do the following:

• Manipulate data items

• Accept arguments and return one value

• Act on each row returned

• Return one result per row

• Can modify the data type

• Can be nested

11



Tell Me / Show Me

Multiple-Row Functions

Multiple-row functions operate on sets of rows to give one

result per group.

• AVG

• COUNT

• MAX

• MIN

• SUM

12



Tell Me / Show Me

Multiple-Row Functions (continued)

Group functions take many rows as input, and return a

single value as output.

SELECT MAX(salary), MIN(salary),

AVG(salary)

FROM employees;

MAX(SALARY) MIN(SALARY) AVG(SALARY)

24000 2500 8775

13



Summary



• Identify appropriate applications of single-row

functions in query statements

• Classify a function as a single-row or multi-row

function

• Differentiate between single-row functions and multi-

row functions and the results returned by each

14



Summary

Practice Guide





INSTRUCTOR NOTES SECTION 17 – Logical Comparisons and Precedence Rules Lesson Slide 1: Logical Comparisons and Precedence Rules What to Watch For Students will need practice understanding and using the AND condition. When using AND, both conditions must be true. If one or both conditions aren't true, the statement is false and then only the OR condition is used, if present. Connections Reinforce the OR condition with an example from data modeling. In the DJs on Demand data model, the entity EVENT had a relationship with two other entities, PRIVATE HOME and PUBLIC PLACE. In the ERD, an arc was drawn across the two relationship lines to signify the OR condition. An EVENT had to be held in either a PRIVATE HOME or a PUBLIC PLACE. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Why Learn It? (continued) No instructor notes for this slide Slide 5: Tell Me / Show Me – LOGICAL CONDITIONS Begin the class with a review question. Write a select statement to find an address in the DJs on Demand database d_venues table that has the word “Primrose” in the description. SELECT address FROM d_venues WHERE address LIKE '%Primrose%' Slide 6: Tell Me / Show Me – LOGICAL CONDITIONS (continued) …WHERE cd_id NOT IN(105, 206, 332); …WHERE cd_id != 105 and cd_id != 206 and cd_id!= 332; Will a query using this WHERE clause select cd_id = 206? No Slide 7: Tell Me / Show Me – LOGICAL Operators Logical operators combine the results of two or more conditions to produce a single result. Use the following as an example, starting first with just one condition on the WHERE, then adding the other two one at a time.



Instructor Resource Guide SELECT job_id, department_id, salary FROM employees WHERE department_id > 50 AND salary > 10000 AND job_id NOT LIKE 'SA%‘; Slide 8: Tell Me / Show Me – AND It will be necessary to reinforce the AND condition when used with OR. Reinforce the order of precedence in that AND will be evaluated first. However, if one of the AND conditions is false, the whole condition is false. In that case, the OR operator is used to restrict the rows. Slide 9: Tell Me / Show Me – OR No instructor notes for this slide Slide 10: Tell Me / Show Me – NOT No instructor notes for this slide Slide 11: Tell Me / Show Me – Rules of Precedence or What Happens First? No instructor notes for this slide Slide 12: Tell Me / Show Me – Rules of Precedence or What Happens First? (continued) These rules are very important. Ask students to view the data in the d_partners table or do a SELECT * from table. Slide 13: Tell Me / Show Me – Rules of Precedence or What Happens First? (continued) These rules are very important. Ask students to view the data in the d_partners table or do a SELECT * from table. Ask students to look at the two examples shown. Without actually querying the table, what output is expected? Accept all answers. Ask students to do a query using each example. Is the output what they expected? Review the output with the students. Slide 14: Summary – In this lesson you have learned to: No instructor notes for this slide Slide 15: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 17 – Sorting Rows Lesson Slide 1: Sorting Rows Connections Relate the ordering of information to the whole process of designing an ERD. Entities in an ERD make up the group of information items that are data requirements for a business. An entity is made up of a group of attributes that are properties of the entity. Before music was available on compact disks (CDs), most music albums were stored on 8-track tapes or vinyl records. If you bought a music tape and wanted to skip to the third song, you had to fast-forward the tape through the first two songs before what you were looking for could be played. The recordings were locked into an order that, many times, was not very convenient and usually not in the order you wanted to listen to them. Today's technology has changed all that. The order in which songs are recorded on a CD is of little significance. With the push of a button, we can play them in any order desired. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Ask students for other ways in which we order our lives. Suggested answers: Library books in library, grocery-store shelves, department stores, parking lots, and file cabinets. Slide 4: Tell Me / Show Me – ORDER BY To reinforce the difference between ascending (ASC) and descending (DESC), ask students the following questions: 1. If your last name is Yonkers, are you in the front or back of the line in ASC order? Back of the line 2. If you wanted to sort your address book in DESC order, what names could appear before mine? Answers will vary depending on the instructor's last name. 3. Would the student who would be first in line in ASC order please raise your hand? Answers will vary depending on the class list of names. Slide 5: Tell Me / Show Me – ORDER BY (continued) No instructor notes for this slide



Instructor Resource Guide Slide 6: Tell Me / Show Me – ORDER BY (continued) Dates can be confusing. The earliest dates are displayed first. Use the dates below to demonstrate that a date in 1985 would be at the top of a list of dates ordered in ascending order. Null values in ASC order are displayed last. 29-JAN-00 16-NOV-99 24-MAY-99 07-FEB-99 09-JUL-98 24-MAR-98 Place the following dates in descending order: 22-MAY-85, null, 10-JAN-04, 17-NOV-55, 21-DEC-98 Answer: null, 10-JAN-04, 21-DEC-98, 22-MAY-85, 17-NOV-55 Slide 7: Tell Me / Show Me – Sorting in Descending Order No instructor notes for this slide Slide 8: Tell Me / Show Me – Using Column Aliases Explain the query execution order. Ask students to have a mental picture of being able to walk into a database to find information just like finding a book in a library. SELECT employee_id, first_name FROM employees WHERE employee_id < 105 ORDER BY last_name; Explain to students that it’s difficult to verify your results when you sort by a column that you’re not SELECTing. In the real world, you would run your query selecting the last_name column until you were sure you were getting the right data. Then you could remove that column from your SELECT statement. Slide 9: Tell Me / Show Me – Sorting with Other Columns No instructor notes for this slide Slide 10: Tell Me / Show Me – Order of Execution No instructor notes for this slide Slide 11: Tell Me / Show Me – Sorting with Multiple Columns No instructor notes for this slide Slide 12: Tell Me / Show Me – Sorting with Multiple Columns (continued) No instructor notes for this slide Slide 13: Summary – In this lesson you have learned to: No instructor notes for this slide



Instructor Resource Guide Slide 14: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 17 – Introduction to Functions – Single Row Functions Lesson Slide 1: Introduction to Functions – Single Row Functions What to Watch For You can't assign too much practice with functions! The next sections present them in depth. Connections Ask students who have used a library computer system to search for a specific book, if they had to enter the book title/author or subject in uppercase or lowercase? Did it matter what case the query was entered in? Most likely the computer program had built-in functions to handle this situation. Having functions built into programs makes data retrieval seamless for the user. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Why Learn It? (continued) Help students organize the SQL syntax for each of the five groups of single-row functions. Use the single-row functions graphic each time a new group is introduced. Slide 5: Tell Me / Show Me – FUNCTIONS No instructor notes for this slide Slide 6: Tell Me / Show Me – FUNCTIONS (continued) No instructor notes for this slide Slide 7: Tell Me / Show Me – SINGLE-Row Versus Multiple-Row Functions No instructor notes for this slide Slide 8: Tell Me / Show Me – SINGLE-Row Functions In SQL, functions are a very powerful feature. Learning the many different functions can be a challenge for students. Focus on helping students see the big picture of the different categories of functions and the syntax for each type. If possible, copy for students the list of functions (link to it). It will help them organize the information in this and subsequent sections about functions. Students could make posters that summarize the different groups of functions. It may also help them organize the information. Display the Single-Row Functions graphic each time you teach a new function group.



Instructor Resource Guide Slide 9: Tell Me / Show Me – SINGLE-ROW FUNCTIONS (continued) Read and discuss what functions are capable of accomplishing. Give examples for each and ask “What advantages do these capabilities offer businesses?” Look for answers that Include:

• Readability (you can store the date with date, hours, minutes, and seconds, but the user may only care about day, month, and year);

• Formatting (numbers in the data base, such as salary data, lack formatting. The user, however, may require numeric data displayed as $ for United States dollars or £ for British pounds);

• Ease of use in data entry (dates entered as Month dd, RRRR are converted to the default format using date conversions).

Slide 10: Tell Me / Show Me – SINGLE ROW FUNCTIONS (continued) Single-row functions are used to manipulate data items. They accept one or more arguments and return one value for each row returned by the query. An argument can be one of the following:

• User-supplied constant • Variable value • Column name • Expression

Features of single-row functions include: • Acting on each row returned in the query • Returning one result per row • Possibly returning a data value of a different type than that referenced • Possibly expecting one or more arguments • Can be used in SELECT, WHERE, and ORDER BY clauses; can be nested

Slide 11: Tell Me / Show Me – MULTPLE-ROW FUNCTIONS Unlike single-row functions, group functions operate on sets of rows to give one result per group. These sets may be the whole table or the table split into groups. The program behind the AVG function for instance, will sum all the values selected, and divide by the number of rows selected. Just like you would do an average in the real world. The MAX function will return the highest value, the MIN the lowest value and so on and so forth. Slide 12: Tell Me / Show Me – MULTIPLE-ROW FUNCTIONS (continued) You can use AVG, SUM, MIN, and MAX functions against columns that can store numeric data. The example on the slide displays the average, highest, lowest salary for all employees. Slide 13: Summary – In this lesson you have learned to: No instructor notes for this slide



Instructor Resource Guide Slide 14: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 17 – Logical Comparisons and Precedence Rules Lesson Vocabulary NOT Inverts the value of the condition

AND Both conditions must be true for a record to be

selected

Precedence Rules that determine the order expressions are evaluated and calculated

OR Either condition can be true for a record to be selected

Try It / Solve It 1. Execute the two queries below. Why do these nearly identical statements produce two

different results? Name the difference and explain why.

SELECT code, description FROM d_themes WHERE code >200 AND description IN('Tropical', 'Football', 'Carnival'); SELECT code, description FROM d_themes WHERE code >200 OR description IN('Tropical', 'Football', 'Carnival');

Solution: The AND condition must satisfy both code and description to return a value. The OR condition will return values that satisfy either condition.SELECT DISTINCT last_name, address,city, state, zip FROM f_customers;

2. Display the last names of all Global Fast Foods employees who have “e” and “i” in

their last names.

Solution: SELECT last_name FROM f_staffs WHERE last_name LIKE '%e%' AND last_name LIKE '%i%';



Instructor Resource Guide 3. “I need to know who the Global Fast Foods employees are that make more than

$6.50/hour and their position is not order taker.”

Solution: SELECT last_name FROM f_staffs WHERE salary > 6.50 AND staff_type!= 'Order Taker';

4. Using the employees table, write a query to display all employees whose last names

start with “D” and have “a” and “e” anywhere in their last name.

Solution: SELECT last_name FROM employees WHERE last_name LIKE 'D%a%e%' or last_name LIKE 'D%e%a';

5. In which venues did DJs on Demand have events that were not in private homes?

Solution: SELECT loc_type FROM d_venues WHERE loc_type NOT IN('Private Home');

6. Which list of operators is in the correct order from highest precedence to lowest

precedence? a. AND, NOT, OR b. NOT, OR, AND c. NOT, AND, OR

Solution: c. NOT, AND, OR



Instructor Resource Guide For questions 7 and 8, write SQL statements that will produce the desired output. 7. Who am I?

I was hired by Oracle after May 1998 but before June of 1999. My salary is less than $8000 a year and I have an “en” in my last name.

Solution: SELECT first_name, last_name FROM employees WHERE last_name LIKE '%en%' and salary < 8000 and hire_date BETWEEN '01-JUN-98' AND '31-MAY-99'; Diana Lorentz

8. What's my email address?

Because I have been working for Oracle since the beginning of 1996, I make more than $9000 per month. Because I make so much money, I don't get a commission

Solution: SELECT email FROM employees WHERE hire_date BETWEEN '01-JAN-96' AND '31-DEC-96' AND salary > 9000 AND commission_pct IS NULL; MHARTSTE An alternative solution for #8 is: SELECT email FROM employees WHERE hire_date > '01-JAN-96' AND salary > 9000 AND commission_pct IS NULL ;



Instructor Resource Guide SECTION 17 – Sorting Rows Lesson Vocabulary Ascending/ ASC Orders the rows in ascending order (the default

order); A-Z

Descending/ DESC Orders the rows in descending order: Z-A

Sort To arrange according to class, kind, or size

Try It / Solve It 1. In the example below, assign the employee_id column the alias of “Number.”

Complete the SQL statement to order the results set by the column alias.

SELECT employee_id, first_name, last_name FROM employees;

Solution: SELECT employee_id AS "Number", first_name, last_name FROM employees ORDER BY "Number";

2. Create a query that will return all the DJ on Demand CD titles ordered by year with

titles in alphabetical order by year.

Solution: SELECT title, year FROM d_cds ORDER BY year, title;

3. Order the DJ on Demand songs by descending title. Use the alias "Our Collection" for

the song title.

Solution: SELECT title AS "Our Collection" FROM d_songs ORDER BY title DESC;



Instructor Resource Guide 4. Order the DJ on Demand songs by descending title. Use the alias "Our Collection" for

the song title.

Solution: SELECT first_name, last_name, student_id, year_in_school, parking_space FROM students WHERE year_in_school = 1 ORDER BY last_name, first_name DESC; (exact syntax names will vary)

5. Write a SQL statement using the employees table and the ORDER BY clause that could retrieve the information in the following table. Return only those employees with employee_id<125.

DEPARTMENT_ID LAST_NAME MANAGER_ID90 Kochhar 100 90 King (null) 90 De Haan 100 60 Lorentz 103 60 Hunold 102 60 Ernst 103 50 Mourgos 100

Solution: SELECT department_id, last_name, manager_id FROM employees WHERE employee_id < 125 ORDER BY department_id desc, last_name desc, manager_id desc



Instructor Resource Guide Extension Activities 1. Limiting values with the WHERE clause is an example of:

a. Projection b. Ordering c. Joining d. Grouping e. Selection

Solution: e. Selection

2. You want to sort your CD collection by title, and then by artist. This can be

accomplished using: a. WHERE b. SELECT c. ORDER BY d. DISTINCT

Solution: c. ORDER BY

3. Which of the following are SQL keywords?

a. SELECT b. ALIAS c. COLUMN d. FROM

Solution: a. SELECT d. FROM

4. Which of the following are true?

a. Multiplication and division take priority over addition. b. Operators of the same priority are evaluated from left to right. c. Parentheses can be used to override the rules of precedence. d. None of the above are true.

Solution: a, b, and c are true



Instructor Resource Guide 5. The following query was written:

SELECT DISTINCT last_name FROM students a. To select all the outstanding students b. To choose last names that are duplicates c. To select last names without duplicates d. To select all last names

Solution: c. To select last_names without duplicates

6. The following string was created using which SELECT clause? Abby Rogers is an order taker for Global Fast Foods a. SELECT first_name ||' ' ||last_name ||' is an ' staff_type ' for Global Fast Foods' b. SELECT Abby Rogers is an ||staff_type||' for Global Fast Foods' c. SELECT first_name,last_name '||staff_type||' for Global Fast Foods' d. SELECT first_name ||' ' ||last_name ||' is an '||staff_type||' for Global Fast Foods'

Solution: d. SELECT first_name ||' ' ||last_name ||' is an '||staff_type||' for Global Fast Foods'

7. Which of the following SELECT clauses will return uppercase column headings?

a. SELECT id, last_name, address, city, state, zip, phone_number; b. SELECT ID, LAST_NAME, ADDRESS, CITY, STATE, ZIP,

PHONE_NUMBER; c. SELECT Id, Last_name, Address, City, State, Zip, Phone_number; d. SELECT id AS ID, last_name AS NAME, address AS ADDRESS, city AS CITY,

state AS STATE, zip AS ZIP, phone_number AS PHONE_NUMBER;

Solution: All of the above will return uppercase column headings by default

8. Which SELECT clause will return the last names in alphabetical order?

a. SELECT last_name AS ALPHABETICAL b. SELECT last_name AS ORDER BY c. SELECT last_name d. SELECT ASC last_name

Solution: a,b,c will return last names in alphabetical order



Instructor Resource Guide 9. Which SELECT clause will return a column heading for employee_id called “New

Employees”? a. SELECT last_name AS "New Employees" b. SELECT employee_id AS New Employees c. SELECT employee AS "New Employees" d. SELECT employee_id AS "New Employees"

Solution: d. SELECT employee_id AS "New Employees"

10. Examine the following query:

SELECT last_name, job_id, salary FROM employees WHERE job_id = 'SA_REP' OR job_id = 'AD-PRES' AND salary >15000;

Which results could not have been returned from this query?

a. Joe Everyone, sales representative, salary 15000 b. Jane Hendricks, sales manager, salary 15500 c. Arnie Smithers, administration president, 20000 d. Jordan Lim, sales representative, salary 14000 Solution: c. Arnie Smithers, administration president, 20000

11. Finish this query so it returns all employees whose last names start with “St”.

SELECT last_name FROM employees

Solution: WHERE last_name LIKE 'St%';

12. What salary values will not be returned from this query?

SELECT last_name, first_name, salary FROM employees WHERE salary BETWEEN 1900 AND 2100;

Solution: Values less than or equal to 1900 or greater than or equal to 2100 will be included in the result set.



Instructor Resource Guide 13. Correct each WHERE clause:

a. WHERE department_id NOT IN 101,102,103; b. WHERE last_name = King c. WHERE start date LIKE "05-MAY-98" d. WHERE salary IS BETWEEN 5000 AND 7000 e. WHERE id =! 10

Solution: a. WHERE department_id NOT IN (101,102,103); b. WHERE last_name = 'King' c. WHERE start_date LIKE '05-MAY-98' d. WHERE salary BETWEEN 5000 AND 7000 e. WHERE id != 10

14. SELECT prefix FROM phone WHERE prefix BETWEEN 360 AND 425 OR prefix IN (206, 253,625) AND prefix BETWEEN 315 AND 620;

Which of the following values could be returned? 625, 902, 410, 499 Solution: 410



Instructor Resource Guide SECTION 17 – Introduction to Functions – Single Row Functions Lesson Try It / Solve It 1. For each task, choose whether a single-row or multiple row function would be most

appropriate:

a. Showing all of the email addresses in upper case letters b. Determining the average salary for the employees in the sales department c. Showing hire dates with months spelled out (September 1, 2004) d. Finding out the employees in each department that had the most seniority (the

earliest hire date) e. Displaying the employees’ salaries rounded to the hundreds place f. Substituting zeros for null values when displaying employee commissions.

Solution: a. single b. multiple c. single d. multiple e. single f. single

2. The most common multiple-row functions are: AVG, COUNT, MAX, MIN, and

SUM. Give your own definition for each of these functions.

Solution: AVG calculates and returns the average value from a set of numeric values COUNT counts and returns the number of non null values from a set of values

MAX returns the highest value from a set of values (most recent date, highest number, or last alphabetically sorted text value)

MIN returns the lowest value from a set of values (oldest date, lowest number, or first alphabetically sorted text value)

SUM returns the sum of a set of numeric values



Instructor Resource Guide 3. Test your definitions by substituting each of the multiple-row functions in this query. SELECT FUNCTION(salary) FROM employees

Write out each query and its results.

Solution: SELECT AVG(salary) RESULT FROM employees ; 8775 SELECT COUNT(salary) FROM employees ; 20 SELECT MAX(salary) FROM employees ; 24000 SELECT MIN(salary) FROM employees ; 2500 SELECT SUM(salary) FROM employees ; 175500



Conceptual and Physical Models

2



What Will I Learn?

Objectives


• Describe the importance of describing information requirements

• Distinguish between a conceptual model and the physical implementation

• List five reasons for building a conceptual data model

• List examples of conceptual models and physical models

3



Why Learn It?

Purpose

When you are able to recognize and analyze information, you can

better understand how things work and potentially make them better.

For example:

• How to make the line at the food counter go faster

• How to make a successful exchange at the store

• How to organize and keep track of your growing CD collection

Also, recognizing and analyzing information helps prevent mistakes

and misunderstanding. For a business, this is important because it

saves time and money.

4



Tell Me / Show Me

Animation

View the following animation and participate in

the discussion afterward.

Was this an easy way to get an order of

sandwiches?

What would you have done differently if you were

the chef?

What would you have done differently if you were

the one placing the order?

sdm_s02_l01_a01

5



Tell Me / Show Me

Comparing Conceptual and Physical

Models

What the person had in mind was the

“conceptual model,” and what the chef created

was the “physical model” of the sandwich tray.

It would have helped if the conceptual model

was understood by both from the beginning.

Can you think of other examples where

accurately describing what you want

(conceptual) is important in getting what you

want (physical)?

sdm_s02_l01_a02

6



Tell Me / Show Me

What is a Conceptual Model?

• Models functional and informational needs

of a business

• Based on current needs and may reflect

future needs

• Deals only with business needs, does not

deal with implementation problems

• Called an “Entity Relationship Model”

• Shown with an “Entity Relationship

Diagram”

sdm_s02_l01_a03

7



Tell Me / Show Me

What is a Conceptual Model (continued)

Businesses use data to increase sales and/or reduce costs. In the

process of creating a data model a business will create a

conceptual model of their data. The purposes of a conceptual model

are to:

• Describe exactly the information needs of the business

• Facilitate discussion

• Prevent mistakes, misunderstandings

• Form important “ideal system” documentation

• Form a sound basis for physical database design

• Document the processes of the business (this is also known as

the “business rules”)

• Take into account regulations and laws governing this industry

8



Tell Me / Show Me


It’s the art of planning, developing, and communicating that

produces a desired outcome.

Data modeling involves getting the requirements down and

using a diagram to describe them. This diagram becomes

the blueprint for designing the actual thing.

The client’s dream (conceptual model) will become a

physical building (physical model).

9



Tell Me / Show Me

Terminology


Conceptual model

Data

Data model

Physical model

10



Summary



• Describe the importance of describing information requirements

• Distinguish between a conceptual model and the physical implementation

• List five reasons for building a conceptual data model

• List examples of conceptual models and physical models

11



Summary

Practice Guide




Entities, Instances, Attributes and

Identifiers

2

Entities, Instances, Attributes and Identifiers


What Will I Learn?

Objectives


• Define and give an example of an entity

• Distinguish between an entity and an instance of an entity

• Name and describe attributes for a given entity

• Distinguish between an attribute and its value

• Distinguish between mandatory and optional attributes,

and between volatile and nonvolatile attributes

• Select and justify a unique identifier (UID) for an entity

3



Why Learn It?

Purpose

Knowing how to organize and classify data makes it

possible to draw useful conclusions about seemingly

random facts. Our technology-rich world produces vast

quantities of facts in need of structure and order.

It is important to learn about entities because they are the

things about which we store data.

For example:

A school needs to store data about (as a minimum):

STUDENTs, TEACHERs, COURSEs, ROOMs, GRADEs.

4



Why Learn It?

Purpose (continued)

It is important to learn about attributes

because they provide more information about

the entities.

Attributes help you be more specific about

what data you need to track.

For example:

• In a restaurant, you need to list the different items in an

order so you know how much to charge.

• When building several sales reports for a department, you

must pick out the correct sales report from a list of reports.

5



Why Learn It?

Purpose (continued)

What about unique identifiers? It is important to learn about

unique identifiers because they distinguish one instance of an

entity from another.

For example:

• In a classroom, you need to distinguish between one

person and another.

• When classifying your CD collection, you need to be able

to locate a particular CD.

• When listing transactions on a financial statement you

need to be able to distinguish between multiple

transactions that occurred on the same day.

6



Tell Me / Show Me

Identifying Purpose

Look at the magazine

advertisements and the

Internet sites identified by

the teacher.

What is the “main thing”

that each ad or website is

about?

7



Tell Me / Show Me

Entity Defined

An entity is:

• “Something” of significance

to the business about which

data must be known

• A name for a set of similar

things that you can list

• Usually a noun

Examples: objects, events,

people

Entities have instances. An

instance is a single occurrence

of an entity.

8



Tell Me / Show Me

Entities and Instances

Entities Instances

PERSON Mahatma Gandhi

PRODUCT Nike Air Jordan

PRODUCT TYPE shoe

JOB electrician

SKILL LEVEL beginner

CONCERT U2 at the Palladium

ANIMAL Dog

CAR Volkswagen beetle

CAR ANIMAL

9



Tell Me / Show Me

Entities and Instances (continued)

• A Dalmatian, a Siamese cat, a cow and a

pig are instances of ANIMAL

• A convertible, a sedan and a station

wagon are instances of CAR

• There are many entities

• Some entities have many instances;

some have only a few

Entities can be:

• Tangible, like PERSON or PRODUCT

• Intangible, like SKILL LEVEL

• An event, like CONCERT

10



Tell Me / Show Me

Entities and Instances (continued)

Is DOG an instance or an entity? It depends:

• If we are interested in different kinds of

animals, it makes sense to think of an

entity ANIMAL with instances DOG, CAT,

HORSE and so on

• But what if we run a dog-breeding business? We need

to keep data on many different breeds of dog, but not on

other species of animal.

• For a dog-breeder, it is more natural to think of an entity

DOG with instances TERRIER, POODLE, LABRADOR

and so on.

11



Tell Me / Show Me

What is an attribute?

Like an entity, an attribute

represents something of

significance to the business.

An attribute is a specific piece of

information that:

• Describes an entity

• Quantifies an entity

• Qualifies an entity

• Classifies an entity

• Specifies an entity

An attribute has a single value.

What is an

Attribute?

sdm_s02_l03_a02

12



Tell Me / Show Me

Attributes have values. An attribute value can be a

number, a character string, a date, an image, a sound,

etc. These are called "data types" or "formats." Every

attribute has a data type.

CUSTOMER family name, age, shoe size,

town of residence, email

CAR model, weight, catalog price

ORDER order date, ship date

JOB title, description

TRANSACTION amount, transaction date

EMPLOYMENT

CONTRACT

start date, salary

ENTITIES ATTRIBUTES

Attributes

13



Tell Me / Show Me

What would be the data types of the CUSTOMER attributes?

For example, “family name” would be a character string.

Attributes are single-valued. Each attribute can have only one

value (at any point in time) for each instance of the entity.







EMPLOYMENT

CONTRACT

start date, salary

Attributes (continued)

ENTITIES ATTRIBUTES

14



Tell Me / Show Me

Some attributes (such as age) have values that constantly change.

These are called volatile attributes.

Other attributes (such as order date) will change rarely, if ever.

These are nonvolatile attributes.

If there is a choice between attributes, use the nonvolatile one. For

example, use birth date instead of age.







EMPLOYMENT

CONTRACT

start date, salary


ENTITIES ATTRIBUTES

15



Tell Me / Show Me


Some attributes must have a value. These are mandatory

attributes. For example: in most businesses that track

personal information, “name” is required.

Others attributes may have a value or be left null. These are

optional attributes. For example: cell phone number is often

not required, except in mobile or wireless applications.

Email address could be a mandatory attribute for EMPLOYEE

if you are modeling an email application. It could be optional

for a CUSTOMER if you are modeling an online catalog.

16



Tell Me / Show Me


A disc jockey (DJ) has to be familiar

with all kinds of music -- songs,

soundtracks, etc. If we were to model a

DJ business, the entity that holds the

collection of music could be called

SONG.

A SONG has attributes.

What attributes would it have?

Can you give examples of values for

each attribute?

sdm_s02_l03_a03

17



Tell Me / Show Me

Identifiers

A SONG has a unique identifier (UID).

A UID is an attribute or combination of attributes that

distinguish one song from another.

How do you find a particular song in the whole

collection? What would be a unique identifier for

SONG?

Think about all the students in the classroom. Each

student is described by several traits or attributes.

Which attribute or attributes allow you to pick a single

student from the rest of the class?

That is the student’s UID.

sdm_s02_l03_a04

18



Tell Me / Show Me

Terminology


Attribute

Data type

Entity

Instance

Mandatory

Intangible

Null

Optional

Single valued

Tangible

Unique identifier (UID)

Volatile

19



Summary



• Define and give an example of an entity

• Distinguish between an entity and an instance of an entity

• Name and describe attributes for a given entity

• Distinguish between an attribute and its value

• Distinguish between mandatory and optional attributes,

and between volatile and nonvolatile attributes

• Select and justify a unique identifier (UID) for an entity

20



Summary

Practice Guide




Entity Relationship Modeling and ERDs

2



What Will I Learn?

Objectives


• Define the meaning of implementation-free as it relates

to data models and database design implementation

• List the four goals of entity relationship modeling

• Identify an entity relationship diagram (ERD)

3



Why Learn It?

Purpose

An entity relationship diagram, abbreviated as ERD, is a

consistent tool that can be used to represent data

requirements regardless of what type of database is used,

or even if a database is not used at all!

4



Tell Me / Show Me

Implementation-Free Models

A good conceptual data model

stays the same regardless of

what type of database the

system is eventually built on.

This is what we mean when we

say that the model is

“implementation-free.”

The data model should stay the

same even if a database is not

used at all (ex. data is eventually

stored on pieces of paper in a

filing cabinet).

Database Types

ER Model

Hierarchical

Database

Network

Database

Relational

Database

5



Tell Me / Show Me

What is an Entity Relationship Model?

• A list of all entities and attributes as well

as all relationships between the entities

that are of importance

• Provides background information such

as entity descriptions, data types and

constraints

• Note: The model does not necessarily

include a diagram, but typically the

diagram is very useful

6



Tell Me / Show Me

Goals of ER Modeling

There are four goals of ER modeling:

• Capture all required information

• Ensure that information appears only once

• Model no information that is derivable from

other information already modeled

• Locate information in a predictable, logical

place

Think of your school record. From your first days

in school, data about you was captured. There is

probably a record of your absences, notes on

discipline, classes taken, and grades earned.

sdm_s02_l04_a02

7



Tell Me / Show Me

DJs on Demand Business Scenario

Read the complete business scenario for the DJ business

below. Then examine the completed ERD.

We started out as a group of friends who organized parties

and customized our own music. Then we thought we’d turn

it into a business to pursue our interests and earn some

money. We called ourselves the “DJs on Demand.”

Everyone who works here is a partner. Every partner has a

specific responsibility. The project manager makes the first

contact with the client to discuss the event. Is it a birthday

party, a wedding, an anniversary, a graduation? What is

the date for the party or event?

8



Tell Me / Show Me

DJs on Demand Business Scenario (continued)

Once that’s decided, the event planner gets in touch with the client

about specific locations, catering, decorations, and other specific

details. The DJ talks with the client about the kind of music wanted.

The project manager supervises the event planners and DJs. He/she

also authorizes expenditures related to a project.

We have a large collection of CDs. Each CD contains several songs,

and the same song can appear on several CDs. We like to classify

each song by type (hip hop, salsa, R & B (rhythm and blues), techno,

salsa, polka, rock, jazz, new age, classical, etc.)

We can propose an initial list of songs to the client depending on the

event. Of course, a client can request other songs as well.

9



Tell Me / Show Me

DJs on Demand Business Scenario (continued)

Our client list is growing. We have a lot of repeat business --

customers who like what we’ve done and ask us to work their

other events. We have some very busy customers who can

have more than one event going on at the same time.

We also have a list of themes that we can use to categorize

these events. For example: a wedding may have a tropical

theme, a party may have a carnival theme, an anniversary

could have a sixties theme, etc. This helps us pick a venue and

also gives us an idea of what the DJ (and other musicians)

should wear. Some partners have a specialty or expertise -- so

a theme also can help us assign the right person to the job.

10



Tell Me / Show Me


(continued)

Events are held either in a public space

or a private home. The event manager

visits both and makes arrangements

with the public-space renter or the

private-home owner.

Since several partners can work on an

event, and an event can be assigned to

several partners, we like to keep track

of who is working on which event. We

keep a log of what each event planner

and DJ has done on an event, and

when they did it.

11



Tell Me / Show Me

Terminology


Implementation-free

Entity relationship diagram (ERD)

12



Summary



• Define the meaning of implementation-free as it relates

to data models and database design implementation

• List the four goals of entity relationship modeling

• Identify an entity relationship diagram (ERD)

13



Summary

Practice Guide





Oracle Academy 1 Database Design

INSTRUCTOR NOTES SECTION 2 – Conceptual and Physical Models Lesson Slide 1: Conceptual and Physical Models Lesson Preparation This lesson begins the actual data-modeling content. Before jumping into definitions of attributes and entities, we first want students to understand the concept of modeling and to recognize models – conceptual vs. physical. This lesson provides reasons for creating a data model in the first place, as opposed to just going ahead and building a database. You may want to ask students, “Have you ever had trouble finding a document in a filing cabinet or folder that someone else organized? The files may have been organized to meet their needs, but not your own.” Data modeling attempts to capture the needs of the business users so that the resulting database is one that everyone can use easily. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn it? Ask: “If you were the manager of a fast-food restaurant, why would you want to collect information about how to make the customer lines at the food counter go faster?” Discuss who benefits from this. Answers include: The faster you can serve people, the greater the profits are for your store! What would be the profits of [USE THE NAME OF A POPULAR RESTAURANT IN YOUR AREA] if they could only serve one customer per hour? Businesses benefit, as well as the customer. You would not return to a restaurant that could serve only one person per hour, would you? Slide 4: Tell Me / Show Me – View the following animation… Play the animation and then ask the class:

• What is the problem in this animation? • What could have been done to make this easier? • Who should do things differently, the chef or the customer?

Feel free to replay and pause the animation if it helps the class discussion.





Key responses would include: • The chef should have asked more questions before preparing the sandwiches

because he is the one who needs to do all of the work! • The woman should have a better-defined order.

Slide 5: Tell Me / Show Me – What the person had in mind was the… Conceptual model: A data model, usually represented by an entity-relationship diagram Physical model: A design for an object (a car, a house, a database, etc.) which includes implementation details such as size, volume, weight, etc.) You can explain the graphics if necessary:

• In the first one, the boy is thinking of getting a nice sports car but is given a practical car instead.

• In the second one, the girl is expecting a big bouquet of flowers but gets something considerably smaller.

Slide 6: Tell Me / Show Me – What is a Conceptual Model? Data: A collection of facts from which conclusions may be drawn Data model: The product of the database design process which aims to identify and organize the required data This animation is similar to the one at the beginning of the lesson, but this time, the customer specifies what she wants from the start. The chef is able to execute the order perfectly. No time is wasted and everyone is happy. You may want to ask students how the same result could be achieved. Answer: The chef could have questioned the customer until he knew exactly what she wanted. If there was an employee manual specifying how to take an order, there would have been a complete order given to the chef by an “order taker.” Slide 7: Tell Me / Show Me – What is a Conceptual Model (continued) No instructor notes for this slide Slide 8: Tell Me / Show Me – Conceptual and Physical Models No instructor notes for this slide Slide 9: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 10: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 11: Summary – Practice Guide No instructor notes for this slide





SECTION 2 - Entities, Instances, Attributes and Identifiers Lesson Slide 1: Entities, Instances, Attributes and Identifiers Lesson Preparation In this lesson, we will start discussing the data model for a DJ (Disc Jockey) business. This is an example business scenario and model that will recur throughout the content. This consistent topic will help the students to learn data-modeling concepts. No diagram will be shown in this lesson; we just want the students to start thinking about the business. What to Watch For Give additional examples of entities (SHOPPING MALL, MOVIE STAR, SHOE) and ask them to name instances of each.

• This will help you determine if they can distinguish between the two. • Make sure they can distinguish between entities and attributes. • Is the attribute single-valued? If not, then it’s an entity. (Use example of CLASS

and STUDENT, where there are many students in one class.) Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? – Knowing how to organize and classify data… Ask students what kind of information they need to know or work with in each of these jobs:

• IT programmer/consultant • Bank manager • Restaurant cashier • Artist • Parent

Slide 4: Why Learn It? – It is important to learn about attributes because… No instructor notes for this slide Slide 5: Why Learn It? – What about unique identifiers? Instance: An occurrence or example. Slide 6: Tell Me / Show Me – Look at the magazine advertisements… Pass magazine ads around the class and/or look at commercial websites. Some suggestions are:

• http://www.nike.com - sports equipment • http://www.weyl.com - beef industry • en-tranz.com - entertainment • http://carmax.com - used cars





• http://www.hallmark.com - greeting cards • http://www.sephora.com - beauty products • http://telstra.com - communication • http://changan.com - automobiles

Ask students to identify the “main thing” about the ads or sites. They will usually come up with a list of entities and instances. Define entities and distinguish them from instances with examples. For example, if you use the Nike website/business with your class, make sure that they see the difference between the entity FOOTWEAR and the instance of the entity as Nike Shoe (or other shoe style). Slide 7: Tell Me / Show Me – An entity is: Entity: A named thing or category of things that is significant to the business and about which data must be known Slide 8: Tell Me / Show Me – Entities and Instances Example: The Entity FRUIT has instances of orange, apple, peach, kiwi, cherry, lime, lemon Slide 9: Tell Me / Show Me – Entities and Instances (continued) Nontangible: Incapable of being perceived by the senses. Tangible: Perceptible by the senses, especially the sense of touch Slide 10: Tell Me / Show Me – Entities and Instances (continued) It would not make sense to have an entity with only one instance. Ask students to think of other examples of “it depends”. Slide 11: Tell Me / Show Me – What is an attribute? Attribute: Characteristic, something that describes, quantifies or specifies an entity An attribute is a piece of information that in some way describes an entity. An attribute is a property of the entity, a detail about the entity. Entities Have Attributes For now, tell students to assume that all entities have at least one attribute. Later, we will discover exceptions to this assumption. Usually, there are many attributes for an entity, but again, we are interested only in those attributes that are of importance to the business. Example: The Entity FRUIT has attributes of name, type, region, date_picked. An instance of this would be: Orange, citrus, west coast, 10-APR-05





Slide 12: Tell Me / Show Me – Examples of Attributes Datatype: A classification identifying one of various types of data, stating the possible values for that type, the operations that can be done on that type, and the way the values of that type are stored Single- valued: Can only have one value at any point for each instance in the entity Slide 13: Tell Me / Show Me – Examples of Attributes Attributes: Point out that the only attributes they need to model are those that the business wants to track. So for example, you may want to track shoe size as an attribute of customer if you are a shoe store, but maybe not if you are a grocery store. It all depends on the business requirements. Every attribute has a datatype. For example, the attribute “name” would be of a datatype like character string, the attribute “salary” would have a number datatype, and the attribute “photograph” would likely be of an image datatype. Attribute Is Single-Valued An attribute for an entity must be single-valued. In more precise terms, an entity instance can have only one value for that attribute at any point in time. This is the most important characteristic of an attribute. The attribute value, however, may change over time. For example: The entity CAR may have attributes “model” and “color.” There can be only one value for these (for example, “beetle” and “green”) at one time, for each instance (i.e. for each individual car). Although model stays constant over the lifetime of the car, color could change. Slide 14: Tell Me / Show Me – Examples of Attributes Volatile: Highly changeable One reason for preferring nonvolatile attributes (if there is a choice) is that volatile attributes will need to be updated frequently. For example, age must be updated every year. How long would this take if we had 1 million customers? If we need to know a customer’s age, we can easily deduce it from the birth date. Slide 15: Tell Me / Show Me – Some attributes must have a value Mandatory: Required Null: A value that is unavailable, unassigned, unknown, or inapplicable; it is not a zero or space Optional: Not required Slide 16: Tell Me / Show Me – A disc jockey (DJ) has to… Have students talk about their favorite DJs and what makes them so good. DJs have to know a lot about music. Talk about the SONG entity, which is the collection of songs and soundtracks. Ask class to give attributes that describe it and values for each attribute.





Possible answers would be title (here they could name their favorite songs), composer, date released/composed, duration, and artist (this one is potentially multivalued, as several artists could perform the same song. Provide the business assumption that each artist’s version is considered a different performance of that song, and we will define it as a different instance in the SONG entity. After all, when you request a song, you often also have a specific artist’s version in mind). Then point out attributes that are mandatory (such as a title) and some that are optional (such as the date it was released). Explain that release date is a better attribute than age because it is less volatile. Slide 17: Tell Me / Show Me – Identifiers Unique identifier: Any combination of attributes and/or relationships that serves, in all cases, to uniquely identify an occurrence of an entity What combination of traits uniquely identifies a single STUDENT? Student’s name? No, there could be two students with the same name. Date of birth? No, there could be two students born on the same day. For almost any combination of student attributes, it is at least possible that two students could have the same combination of values. This is why for entities such as STUDENT, we create an artificial student number or student ID. Ask the class if title would be sufficient to uniquely identify a SONG. Answer: No, because there are cases of songs with the same title.

• Would a combination of attributes work? Probably. (Example: title and composer and artist.)

• Could you decide to just assign a unique ID to each SONG, similar to Student number? Yes.

Slide 18: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 19: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 20: Summary – Practice Guide No instructor notes for this slide





SECTION 2 – Entity Relationship Modeling and ERDs Lesson Slide 1: Entity Relationship Modeling and ERDs Lesson Preparation No further lesson preparation information. What to Watch For Make sure that information is stored only once – the same attribute should not be repeated in another entity if it is describing the same information. For example: price can be an attribute of FOOD ITEM, but total price of an ORDER can be derived so it should not be an attribute there. Assess for understanding by asking students if entities change depending on the type of database, computer, or programming language used. Answer: No. This is what is meant when we say that data modeling is “implementation-free.” Connections Reiterate that the ERD is a tool for discussion, especially when designing a system. It gives you and the customer something to react to, validate, and correct. Ask students to think back to the Dream House activity. When the student who wanted the dream house saw the picture that the other student had drawn, the student knew that the other person either (a) got it right! or (b) got it wrong. That’s how an ERD works. Other examples that help illustrate this point: getting a haircut based on a picture in a magazine (have you ever forgotten the picture?); having a dress made from a picture in a magazine (what if you could only explain it?); describing a gift you want to your parents who’ve never seen this item. Pictures help! Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn it? Entity relationship diagram (ERD): A drawing that is used to represent a data model Tell students that they need to know what an ERD looks like – they will be drawing ERDs in the next section and throughout the course. This is where students become architects and draw their clients’ “dream” models. Slide 4: Tell Me / Show Me – Implementation-Free Models Implementation free: Not dependent on the physical model Database Types: Hierarchical, Relational, Network This picture shows us that an ER model captures business information that can be used as a basis for any database. The ER model tells us something about the business, not about





the implementation. Having said that, in practice, the majority of the ER models lead to relational database implementations. Slide 5: Tell Me / Show Me – What is an Entity Relationship Model? No notes for this slide. Slide 6: Tell Me / Show Me – Goals of ER Modeling An Entity Relationship Diagram (ERD) is a picture, a representation of the model or a part of the model. Discussion points using the school-record example: • Where does the school store student information? How is it stored? • Who is responsible for updating changes to student information? • What information indicates that a student is eligible for graduation? • Have you ever updated information only to be asked to do it again? • What happens to student data when the school gets new database computers? • How do you locate your information among all the other student records? • How do your grades not get confused with another student with the same last name? Slide 7: Tell Me / Show Me – DJs on Demand Business Scenario The “DJs on Demand” scenario is referenced in several lessons later in the course, in which the completed ER model is built up piece-by-piece. You will be showing the ER model to the class as an example of a complete data model. This will contain supertypes/subtypes, arcs, barred relationships, and other data-modeling techniques that you have not taught yet. Just explain that by the end of the course, they will know what it all means. For now, focus on the entity names in softboxes and on the attributes inside the softbox, which are mandatory (*) and which are optional (o). Point out the relationships. These are coming up in the next section. Drawing conventions will be discussed in another lesson, so you may not want to use the terms “softbox” when going over the ERD. You may not even want to go over the drawing conventions for mandatory and optional attributes (* vs. o), but it is all right if some students deduce this from your demonstration. Slide 8: Tell Me / Show Me – DJs on Demand continued: No instructor notes for this slide Slide 9: Tell Me / Show Me – DJs on Demand continued: No instructor notes for this slide Slide 10: Tell Me / Show Me – DJs on Demand continued: No instructor notes for this slide





Slide 11: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 12: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 13: Summary – Practice Guide No instructor notes for this slide





Practice Solutions SECTION 2 – Conceptual & Physical Models Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Physical model A design for an object (a car, a house, a database,

etc.) which includes implementation details such as size, volume, weight, etc.)

Conceptual model A data model, usually represented by an entity-

relationship diagram.

Data A collection of facts from which conclusions may be

drawn.

Data model The product of the database design process which

aims to identify and organize the required data Try It / Solve It 1. You will be working in pairs for this activity.

• One student describes his/her “dream house” while the other student attempts to draw it.

You can discuss specific details, but the student describing the house is not allowed to see what is being drawn until after time is called.

• After sharing your drawing describe the importance of accurately describing

information requirements.





Solution: The objective of the dream-house activity is for students to demonstrate precise communication as a means to facilitate discussion and prevent mistakes and misunderstandings. Working in pairs, one student describes his/her “dream house” while the other student attempts to draw it. The pairs can discuss specific details, but the student describing the house is not allowed to see what is being drawn until after time is called.

• Collect student drawings and tape to the board/wall. • Ask volunteer student pairs to describe the discrepancies between what they

thought was being described and what was actually drawn. • Solicit student ideas on how they would improve the communication process

if they were to do the same activity again. Possible answers may include: Describe shapes and colors. Describe relative sizes (bigger than a hut, smaller than a hotel, etc.) Be specific (2 doors, 3 stories, 5 windows, etc.). Make comparisons to known things (similar to Mary’s house, like a castle, etc.). Other ways to test for understanding: Make sure that the students understand the difference between a conceptual and a physical data model by presenting examples and asking them to identify them as conceptual or physical:

• Blueprint of a house versus a house • Sketch of an outfit/dress/suit versus the real thing • Recipe for a cake versus the cake itself

If you can show actual samples of the above (house plans, draw a dress/suit on the board, print out a recipe), that would drive home the point even better. Feel free to supplement with other examples that are more familiar or accessible to you.

2. Review the scenario below. Identify the conceptual model and the physical model

from the scenario.

Zoe was about to go into a store to purchase drinks for the birthday party scheduled for that evening. Zoe knows that she needs drinks for 48 people and is expecting the store to accept a check for payment and to provide her with some assistance carrying the product to her car. Zoe wants to have carbonated drinks, non-carbonated drinks, and sugar free drinks. She is expecting to purchase 4 six packs. Zoe enters the store and discovers the entire drink distribution system is automated. She also discovers that the drinks come in varying package sizes and that she must choose the correct vending option for the products to be disbursed. Drinks are packaged in four packs, six packs, and ten packs, which is not what Zoe expected.





Solution: Conceptual model – Selecting products, providing a check for payment to a person, and having a person assist with carrying the products out of the store. Physical implementation – Automated vending system requiring payment for each product distributed. No one available to assist with carrying the products out of the store.

3. Provide five reasons for creating a conceptual data model.

Answers will vary but can include any of the following: • Describe exactly the information needs of the business • Facilitate discussion • Prevent mistakes, misunderstandings • Form important “ideal system” documentation • Form a sound basis for physical database design • Document the processes of the business (this is also known as the “business

rules”) • Take into account regulations and laws governing this industry

4. List two examples of conceptual models and physical models.

Answers will vary but should illustrate the understanding that the conceptual model is the thought and the physical model is the actual implementation of the thought.





SECTION 2 - Entities, Instances, Attributes and Identifiers Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Mandatory Required.

Nontangible/ Intangible Incapable of being perceived by the senses.

Unique Identifier (UID) Any combination of attributes and/or relationships

that serves, in all cases, to uniquely identify an occurrence of an entity.

Instance An occurrence or example.

Attribute Characteristic, something that describes, quantifies or specifies an entity.

Optional Not required.

Entity A named thing or category of things that is significant to the business and about which data must be known.

Null A value that is unavailable, unassigned, unknown, or inapplicable; it is not a zero or space.

Volatile Highly changeable.

Tangible Perceptible by the senses, especially the sense of touch

Datatype A classification identifying one of various types of data, stating the possible values for that type, the operations that can be done on that type, and the way the values of that type are stored

Single Valued Can only have one value at any point for each instance in the entity





Try It / Solve It 1. Consider the entity STUDENT. You are all students in a class. However, each one of

you is a unique instance of that entity. Your teacher will lead you through an exercise to demonstrate this.

Solution: Say, “STUDENTS please stand up.” Have everyone sit down and then say, “Julie Miller (or some specific student in your class), please stand up.” Then explain that while they are all students, Julie Miller is a specific instance of STUDENT. Have students write on a 3 x 5 note card the answers to the questions below, or fill out a preprinted sheet of paper with the following information:

• Month of birthday • Color of shirt/blouse • Shoe color • Color of backpack/school bag • Glasses/no glasses • Year in school • Eye color • Has a pet cat/dog/bird • Right/left-handed • Number of brothers and sisters

Note: The specific traits can be varied as long as there are six or more different traits. You need at least six traits to uniquely identify a student. Collect the card/paper from each student. Ask all students to stand up. Randomly select one student’s card/paper. Ask a question for each trait that the students recorded. You are trying to eliminate other students until you are left with only the student whose card you have. This student is your INSTANCE. For example:

a. Will all those students who were born before or after (the month listed on the selected card) please sit down?

b. Will all those students who are not wearing shoes of color (the color on selected card) please sit down?

c. Will all those students who (wear/not wear) glasses please sit down? d. Will all those students who do not have eye color (eye color on selected card)

please sit down? e. Will all those students who are (left/right)-handed please sit down? f. Will all those students who have fewer or more siblings than (number of

brothers and sisters) please sit down? Make sure students can distinguish between entities and instances. Ask them how you can distinguish one student from another. You can ask them to provide answers now





(name, gender, hair color, etc.), but tell them that these are attributes and will be discussed further later. Ask students which traits would make good attributes to identify someone:

• Does the month of your birthday ever change? • Does your shoe color change? • What other traits could be added if shoe color and glasses are eliminated?

2. Think about the last time you went to get a haircut, permanent, manicure, or other

service from a barbershop or hair salon.

Discuss the business of a barbershop or hair salon. Name the entities that are the “main things” about this business. Give examples of instances for each entity.

Solution:

• Customer – Vishal Gupta • Services – color, cut, permanent wave, manicure, shampoo • Employees/technicians – stylist, shampoo person, cashier, receptionist • Products – shampoo, color, styling gel, lotion • Tools – hair dryer, scissors

Note: In naming entities, the class may also be including attributes. If they do this, correct them, and identify them as attributes, and tell them that we will discuss the difference more in the next lesson.

3. The goal of this activity is to learn to make a distinction between an entity, an

attribute, and an instance of an entity. List which of the following concepts you think is an entity, attribute, or instance. If you determine that one is an entity, then give an example of an instance. If you determine that one is an attribute or an instance, give a sample entity name. For the last three rows, find a concept that fits.

Concept Entity? Attribute? Instance? Example instance or Entity Vehicle Diet Cola Price Customer number Green Entity Cookie Attribute Cookie Instance Cookie





Solution: In order to guide students in the direction of the given solution, you may want to provide business contexts for each concept, such as:

• Vehicle (a car-rental agency) • Diet Coke (a restaurant) • Price (a department store) • Customer number (an online catalog) • Green (a botanical garden) • Cookie (a restaurant)

Alternative answers may be considered acceptable, if the student can argue successfully and provide a business context or rule for it.

4. The goal of this practice is to recognize attributes for an entity.

The three entities that play a role in a DJ business: SONG, EVENT, and CUSTOMER are listed as the first three column headings of the table below. The fourth column contains a collection of attributes. Use a check mark to indicate if the attribute listed could be an attribute for the entities listed. (For example, could Title be an attribute for Song, for Event, and for Customer?)

SONG EVENT CUSTOMER

Title Description Venue First Name Phone Number Release date Last Name Type Email address





Solution: The three entities that play a role in a DJ business: SONG, EVENT, and CUSTOMER are listed as the first three column headings of the table below. The fourth column contains a collection of attributes. Use a check mark to indicate if the attribute listed could be an attribute for the entities listed. (For example, could Title be an attribute for Song, for Event, and For Customer?)

SONG EVENT CUSTOMER

X Title X X Description X Venue X First Name X Phone Number

X Release date X Last Name

X X Type X Email address

5. From the list of attributes provided, identify which attribute could be the unique

identifier of each entity.

Entity: STUDENT Attributes: student ID, first name, last name, address UID: student ID Entity: MOVIE Attributes: title, date released, producer, director UID: a combination of title and date released, or an artificial UID such as movie ID Entity: LOCKER Attributes: size, location, number UID: number

6. Read the given business scenario and walk through the steps below.

“I’m the owner of a small movie rental store. We have over 3,000 movies that we need to keep track of.

“Each of our movies has a DVD or VHS tape number. For each movie, we need to know its title and category (e.g., comedy, suspense, drama, action, war, or sci-fi).





“Yes, we do have multiple copies of many of our movies.

“We give each movie a specific ID, and then track which DVD or VHS contains the movie. A movie can be either DVD or VHS format.

“We always have at least one DVD or VHS tape for each movie we track, and each DVD or VHS tape is always a copy of a single, specific movie.

“Our DVDs and VHS tapes are very long. We don’t have any movies that require multiple DVDs or VHS tapes.”

a. Write a list of nouns used in the scenario.

owner, store, movie, DVD, VHS tape

b. Name each entity. media, customer, movie, actor

c. Is each instance of the entity uniquely identifiable? Which attribute or attributes could serve as the unique attribute to identify the entity? movie number, customer number, actor name, media number

7. Identify the business rules contained in the following scenario.

“We are frequently asked for movies starring specific actors. John Wayne and Julia Roberts are always popular. So we’d like to keep track of the star actors appearing in each movie. Not all of our movies have star actors. Customers like to know each actor’s “real” birth name and date of birth. We track only actors who appear in the movies in our inventory.”

Solution: Track actors for each movie in the inventory. Track actor birth names for each actor Track actor date of birth for each actor

8. Identify the business rules contained in the following scenario.

“We have lots of customers. We rent videos only to people who have joined our ‘video club.’ To belong to our club, they must have good credit. For each club member, we’d like to keep their first and last name, current phone number, and current address. And, of course, each club member has a membership number.





Then we need to keep track of what movie each customer currently has checked out. A customer may check out multiple video tapes at any given time. We just track current rentals. We don’t keep track of any rental histories.”

Solution:

• Customers must have a membership number • Movies are only rented to customers • Customers must have a good credit rating • Customer information captured includes first and last name, phone number,

and address. • Customer rental history includes current rental only • Customer rental history can include more than one movie

9. Age is an example of what type of attribute? Volatile attribute 10. Birth date is an example of what type of attribute? Non-volatile attribute 11. Read the business scenario of a fast-food restaurant below:

We are a small fast food business. Our menu features food items that can be ordered by a customer. A customer places an order at the counter and indicates what food items he/she would like on that order.

Lately we’ve noticed that we have some regular customers, so we started asking them for information – such as name and address, so we can mail them coupons when we have specials.

a. Using the restaurant entities ORDER, FOOD ITEM, AND CUSTOMER, identify

the attributes for each entity. b. Where possible, indicate whether the attribute is mandatory or optional. c. Where possible, pick out the UIDs for each entity

Solution: This restaurant business scenario is an offshoot version of the progressive project, Global Fast Foods, which students will be building throughout the course. There is not a definitive solution for this activity but the answer can be similar to the Global Fast Foods model. Some students may want an entity called MENU, with food item as an attribute. Be careful with this one: although MENU could be a valid entity, food item as an attribute would be repeating: there would be many different food items on a menu. Therefore, even with MENU as an entity, you would still need FOOD ITEM as another entity. Attributes of menu could be name, hours served, etc. Ask students why they would choose to make an attribute mandatory or optional. This makes them start thinking about business rules.





UID for ORDER could be number, UID for FOOD ITEM could be name (or ID), and UID for CUSTOMER could be name and address together or ID.





SECTION 2 – Entity Relationship Modeling and ERDs Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Implementation-free Not dependent on the physical model.

Entity relationship diagram (ERD)

A drawing that is used to represent a data model.

Try It / Solve It 1. True or False: To be described as implementation-free a data model must be changed

to accommodate the database system onto which it is built. False 2. True or False: To be described as implementation-free a data model must not change

to accommodate the database system onto which it is built. True 3. List four goals of entity relationship modeling.

• Capture all required information • Ensure that information appears only once • Model no information that is derivable from other information already

modeled • Locate information in a predictable, logical place

4. An ___ERD_______ is a consistent tool that can be used to represent data

requirements regardless of what type of database is used.



Identifying Relationships

2



What Will I Learn?

Objectives


• Interpret and describe relationship optionality

• Interpret and describe relationship cardinality

• Relate entities by applying the rules of cardinality and

optionality

3



Why Learn It?

Purpose

Being able to identify the relationships between entities makes

it easier to understand the connections between different

pieces of data.

It helps you see how different parts of a system affect each

other. For example, the entities STUDENT and COURSE are

related to each other.

To accurately model the business, the relationships are as

important as the entities themselves.

4



Tell Me / Show Me

Relationships in Families

What is the relationship between you and your aunt, you and

your uncle, your cousins, your grandmother, etc? What would a

society be like that did not categorize relatives as aunts, uncles,

cousins, grandmothers and grandfathers but only by their name?

How could you tell someone that Jenny was your cousin?

It would be a long and potentially confusing introduction, like

“This is Jenny, who is the child of the woman who has the same

parents as my parent who is a woman,” as opposed to “This is

Jenny, my mother’s sister’s child,” or “This is Jenny, my aunt’s

child,” or the simplest one “This is Jenny, my cousin”.

Notice that we still use a basic relationship in the longest

introduction -- that of child to parent. Without that relationship it

would be very difficult to introduce anyone beyond giving their

name!

5



Tell Me / Show Me

Relationships in Data Models

Relationships:

• Represent something of significance/importance to the

business

• Show how entities are related to each other

• Always exist between two entities (or one entity twice)

• Always have two sides

• Are named at both ends

• Have an optionality

• Have a degree or cardinality

6



Tell Me / Show Me

What is Optionality in a Relationship?

Relationships are either mandatory or optional. Based on what you

know about instances of the entities, you can determine optionality

by answering four questions:

• Must every employee have a job? In other words, is this a

mandatory or optional relationship for an employee?

• Can employees have more than one job?

• Must every job be done by an employee? (In other words, is this

a mandatory or optional relationship for a job?)

• Can each job be done by more than one employee?

7



Tell Me / Show Me

What is Cardinality in a Relationship?

Cardinality of a relationship determines the degree of a

relationship. It answers “how many.”

For example:

• How many jobs does an employee hold? One or more? Just

one?

• A job may be held by how many employees? Just one? One or

more?

8



Tell Me / Show Me

Optionality and Cardinality

Examples:

Each EMPLOYEE must hold one and only one JOB

Each JOB may be held by one or more EMPLOYEEs

Each PRODUCT must be classified by one and only one

PRODUCT TYPE

Each PRODUCT TYPE may classify one or more

PRODUCTs

9



Tell Me / Show Me

Relationships

• Each SEAT may be sold to one

or more PASSENGERs

• Each PASSENGER may

purchase one SEAT

• SEAT is sold to a PASSENGER

(or PASSENGERs -- hence,

overbooking)

• PASSENGER purchases or

books a SEAT

SEAT

PASSENGER

10



Tell Me / Show Me

Business Scenario 1

What are the relationships in the

following business scenario?

“We like to classify all our music, each

song or soundtrack, by type. The

different types are rock, jazz, country,

classical, pop, new age, etc. We can

add new types as the need arises. In

fact, we recently added a new type for

rap music. We realize that a song can

really be classified under more than one

type, but for our purposes we select

only one main classification type for

each song."

RELATIONSHIP

SONG

(music/soundtrack) is

classified by TYPE

TYPE is a classification

for SONG

11



Tell Me / Show Me

Business Scenario 1 (continued)

SONG has a TYPE: optionality and cardinality

Optionality = Must or may?

Each SONG must be classified by one (and only one) TYPE.

Each TYPE may be a classification for one or more SONGs.

Cardinality = How many?

Each SONG must be classified by one (and only one) TYPE.

Each TYPE may be a classification for one or more SONGs.

new age

rock

classical

pop

jazz

country

Stairway to Heaven

Minute WaltzPachelbel Canon

Green Dolphin Street

Thriller

Stand By Your Man

TYPE

SONG

12



Tell Me / Show Me


SONG has a TYPE

What if there is no TYPE for a SONG?

Do the business rules state that every SONG has a TYPE? If yes, then an additional TYPE needs to be added.

new age

rock

classical

pop

jazz

country

Stairway to Heaven



Thriller

Stand By Your Man

TYPE

SONG

Amazing

Grace

13



Tell Me / Show Me


SONG has a TYPE

Can you have a TYPE with no SONG?

Why would you have a TYPE with no SONG?

new age

rock

classical

pop

jazz

country

Stairway to Heaven



Thriller

Stand By Your Man

TYPE

SONG

14



Tell Me / Show Me

Business Scenario 1

(continued)

SONG has a TYPE

How many TYPEs can a

SONG belong to?

Business rules determine

cardinality.

If a SONG can belong to

more than one TYPE the

cardinality would be stated

as:

Each SONG must be

classified by one or more

TYPEs.

new age

rock

classical

pop

jazz

country

Stairway to Heaven



Thriller

Stand By Your Man

TYPE

SONG

15



Tell Me / Show Me

Business Scenario 2

What are the relationships in the

following business scenario?

“In our restaurant, customers come up

to the counter and place their orders. A

customer can order for himself/herself

or for a whole group of people. For

example, if a mother orders for herself

and her children, we consider that

mother to be the customer who owns

the order and who is responsible for

payment. Of course, the customer can

place as many orders as he/she wants.”

RELATIONSHIP

CUSTOMER places

ORDERS

An ORDER is placed

by one CUSTOMER

16



Tell Me / Show Me

Business Scenario 2

(continued)

CUSTOMER has ORDERs:

optionality and cardinality

Optionality = Must or may?

Each ORDER must be placed by

one (and only one) CUSTOMER.

Each CUSTOMER must place

one or more ORDERs.

Cardinality = How many?

Each ORDER must be placed by

one (and only one) CUSTOMER.

Each CUSTOMER must place

one or more ORDERs.

Linda

Mel

Krishna

Order No. 100

-French fries

- Large soda

Order No. 102

- Apple pie

Order No. 77

-Hamburger

- Salad

- Fruit cup

Order No. 10

-Vegetarian platter

- Orange juice

ORDER

CUSTOMER

17



Tell Me / Show Me

Business Scenario 3

A relationship can relate an

entity to itself. Examine the

following scenario.

“We need to keep track of our

employees and their

managers. Every employee

has one manager, including

the managing director, who

manages him/herself. Each

manager can manage several

employees.”

Since managers are also

employees, there is only one

entity here: EMPLOYEE.

RELATIONSHIP

An EMPLOYEE manages EMPLOYEEs

An EMPLOYEE is managed by one EMPLOYEE

18



Tell Me / Show Me

Terminology


Cardinality/Degree

Relationship

Optionality

19



Summary



• Interpret and describe relationship optionality

• Interpret and describe relationship cardinality

• Relate entities by applying the rules of cardinality and

optionality

20



Summary

Practice Guide




ER Diagramming Conventions

2



What Will I Learn?

Objective


• Construct ER diagram components that represent

entities and attributes according to diagramming

conventions

3



Why Learn It?

Purpose

People speak different

languages throughout the

world, but some signs are

understood globally.

Guess the meaning of these

signs.

International Signs

1 2 3 4

5 6 7

4



Why Learn It?

Sign Review

How well did you do?

Did you guess the

meaning of most

signs?

International Signs

1. Crosswind 4. Lane for slow vehicles 6. Low clearance

2. Roundabout 5. Stop in Brazil 7. Mr. Yuk

3. No entry for vehicles carrying more than a certain quantity of

explosives or readily inflammable substances

Key:

1 2 3 4

5 6 7

5



Tell Me / Show Me

Shared Convention

It is efficient to communicate

information in a way that can be

easily understood by many

people.

ER diagramming is like that --

you may say or write things

differently because of the way

you speak, your accent, and so

on, but everyone draws

diagrams according to the

same conventions.

A Shared

Convention

6



Tell Me / Show Me

DJs on Demand: Clients, Events,

and Types

"Our client list is growing. We have a

lot of repeat business -- customers

who like what we’ve done who ask

us to work for them again. We have

some very busy customers who can

have more than one event going on

at the same time. Each partner has

some specialty or expertise -- so

when it’s appropriate, we like to

classify our events by theme to help

us assign the right person (partner)

to the job. An event theme can be a

beach party, medieval, carnival, retro

sixties or seventies, etc. We keep

adding event themes as we go."

CLIENT

# number

# first name

# last name

o phone

number

EVENT

# id

* name

* date

o description

o cost

THEME

# code

* description

7



Tell Me / Show Me

ER Drawing Conventions

Entities are represented by

softboxes.

Entity names go in the

softboxes.

Entity names are always

singular and written with all

capital letters.

CLIENT

EVENT THEME

8



Tell Me / Show Me

Drawing Conventions

Attributes are listed under the

entity names.

Mandatory attributes are

marked with an asterisk: “*”

Optional attributes are marked

with a circle: “o”

Unique identifiers are marked

with a hash sign: “#”

CLIENT

# number

* first name

* last name

* phone number

o email address

EVENT

# id

* name

* date

* cost

* description

THEME

# code

* description

9



Tell Me / Show Me

Drawing Conventions

(continued)

Relationships are lines that

connect entities.

These lines are either solid or

dashed.

These lines terminate in a

“single toe”

or a “crow’s foot” at the end of

each entity.

You will learn more about the

meaning of relationship lines in

the next lesson.

Single Toe

Crow’s Foot

CLIENT

# number

* first name

* last name

* phone number

o email address

EVENT

# id

* name

* date

* cost

* description

THEME

# code

* description

10



Tell Me / Show Me

Terminology


Softbox

11



Summary

Objective Summarized


• Construct ER diagram components that represent

entities and attributes according to diagramming

conventions

12



Summary

Practice Guide




Speaking ERDish and Drawing

Relationships

2

Speaking ERDish and Drawing Relationships


What Will I Learn?

Objectives


• State relationships between entities in precise words

(ERDish)

• Draw and label relationships correctly on an ERD

3



Why Learn It?

Purpose

Most businesses have a unique terminology (words which

have a special meaning within that business) that people

speak in order to communicate information.

Data modeling also has a unique terminology as well,

which we call ERDish for the purposes of this class.

Learning how to create ERDs and speak ERDish gives you

a common terminology with your clients and with Database

Administrators who will implement your design.

4



Tell Me / Show Me

Review A Scene

View the following scene between

the waiter placing orders and the

chef.

Why did the waiter have trouble at

the end?

sdm_s03_l03_a01

5



Tell Me / Show Me

ERD Language

ERDish is the language we use to state relationships between entities in an ERD.

You have already been speaking and writing it, when you identified relationships and specified optionality and cardinality. We are simply breaking down each ERDish sentence into its components.

Breaking Down ERDish

EMPLOYEE DEPARTMENTworking in

the cost

center for

6



Tell Me / Show Me

The components of

ERDish

1. EACH

2. Entity A

3. OPTIONALITY (must be/may be)

4. RELATIONSHIP NAME

5. CARDINALITY (one and only one/one or more)

6. Entity B

EMPLOYEE DEPARTMENTworking in


1. EACH

2. EMPLOYEE (entity A)

3. MUST BE (optionality, solid line)

4. WORKING IN (relationship name)

5. ONE (cardinality, single toe)

6. DEPARTMENT (entity B)

Since each relationship has two sides, we read the first relationship from left to right (or top to bottom, depending on the ERD layout).

7



Tell Me / Show Me

EMPLOYEE DEPARTMENT


1. EACH


3. MAY BE (optionality, dotted line)

4. THE COST CENTER FOR (relationship name)

5. ONE OR MORE (cardinality, crow’s foot)


the cost

center for

The components of

ERDish (continued)

1. EACH

2. Entity A




6. Entity B

Now we read the second relationship from right to left.

8



Tell Me / Show Me

EMPLOYEE DEPARTMENT

working in


1. EACH


3. MUST BE (optionality, solid line)

4. WORKING IN (relationship name)

5. ONE AND ONLY ONE

(cardinality, single toe)


the cost

center for

1. EACH


3. MAY BE (optionality, dotted line)

4. THE COST CENTER FOR

(relationship name)

5. ONE OR MORE (cardinality, crow’s

foot)

6. EMPLOYEE (entity B)

The components of

ERDish (continued)

1. EACH

2. Entity A




6. Entity B

Now bring it together.

9



Tell Me / Show Me

Terminology


ERDish

10



Summary



• State relationships between entities in precise words

(ERDish)

• Draw and label relationships correctly on an ERD

11



Summary

Practice Guide



Before the practice activities review the animation below.

sdm_s04_l02_a02


Matrix Diagrams

2

Matrix Diagrams


What Will I Learn?

Objectives


• Identify relationships using a matrix diagram

• Draw an ERD from a matrix diagram

3

Matrix Diagrams


Why Learn It?

Purpose

It is useful to know

more than one way

of discovering

relationships.

The matrix diagram

is a good way to

make sure that we

haven’t missed any

relationships --

especially useful

when you are

dealing with a lot of

entities.

It may be simple enough

to identify relationships

given three entities.

But what about finding

relationships when you

have thirteen or more

entities?

TEACHER COURSE

CLASS

TEACHER COURSE STUDENT

CLASS EXAM SEMESTER

CAFETERIA GRADE CLUB

CLASSROOM SCHOOLSCHOOL

EQUIPMENT

…etc. MAINTENANCE

STAFF

4

Matrix Diagrams


Tell Me / Show Me

Business Scenario

"I work for a travel agency.

I keep a record of the

countries that our

customers have visited

and the landmarks they’ve

seen in each country. It

helps us customize tours

for them."

We can use the matrix

diagram to uncover

relationships.

TRAVELER COUNTRY LANDMARK

TRAVELER

COUNTRY

LANDMARK

TRAVELER

LANDMARK

COUNTRY

MATRIX DIAGRAM

5

Matrix Diagrams


Tell Me / Show Me

Matrix Diagrams

Relationships

discovered via the

matrix diagram are

drawn on the ERD.

Matrix diagrams do not

show optionality and

cardinality.

“Each COUNTRY may

be visited by one or

more TRAVELERs”.

TRAVELER COUNTRY LANDMARK

TRAVELER

COUNTRY

LANDMARK

visit have seen

visited by the location of

seen by located in

TRAVELER COUNTRY

LANDMARK

visit

visited by

the location of

located inhave seen

Seen by

6

Matrix Diagrams


Tell Me / Show Me

Terminology


Matrix diagram

7

Matrix Diagrams


Summary



• Identify relationships using a matrix diagram

• Draw an ERD from a matrix diagram

8

Matrix Diagrams


Summary

Practice Guide





INSTRUCTOR NOTES SECTION 3 – Identifying Relationships Lesson Slide 1: Identifying Relationships Lesson Preparation The previous section introduced entities and attributes. Relationships are the third component of a data model (the “R” in “ER modeling”). This section starts by identifying relationships between entities. Then it examines the characteristics of and rules regarding relationships. What to Watch For Have students go over each of the relationships shown in the Try It / Solve It activities, and change the business rules (example: any WAITER can take any ORDER from any table). Then have them restate the relationship with the revised cardinality and/or optionality. Connections We could use a familiar example here because it has many possibilities: TEACHERS/COURSES/STUDENTS Teachers may teach courses (part-time teachers may have the term off). Are all courses taught by teachers? What about online courses? Students attend courses. Must students take a course to be considered a “student”? Can there be a course with no student? Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Relationship: A connection or association between objects Other discussion points for why it is important to understand relationships: What is the relationship between student and library book? (What would you do if you received a fine for a book checked out by another student?)

• You would certainly protest because the student who checked out the book (this is the relationship) should also be responsible for any associated fines.

• This emphasizes the importance of clarifying relationships, especially in a business.

Slide 4: Tell Me / Show Me – What is the relationship between you and… No instructor notes for this slide



Instructor Resource Guide Slide 5: Tell Me / Show Me – Each Relationship: Ask students: have you ever been scheduled for an airplane flight and heard the check-in desk attendant ask if anyone wanted to give up their seat because the plane was overbooked? Why does an airline sell one seat to two people? Is every seat sold to more than one person? Why does it happen sometimes and not all the time? Is it normal for a person to buy more than one seat for himself/herself on a plane? Slide 6: Tell Me / Show Me – Each SEAT may be sold… No instructor notes for this slide Slide 7: Tell Me / Show Me – Business scenario describing relationships: Point out that this statement describes the basic relationship between SONG and TYPE, but in order to fully capture the business rules, we need to revise the sentence to include optionality and cardinality. Slide 8: Tell Me / Show Me – SONG has a TYPE: optionality and cardinality Optionality: Must or may? Encourage discussion about the business rules and how they affect optionality: Must every SONG have a TYPE? Cardinality: How many? Slide 9: Tell Me / Show Me – SONG has a TYPE Can you have a SONG that doesn’t fall under any one TYPE? Point out that in the diagram, all SONGs are classified by a TYPE. How would you classify a religious song when you don’t have a type called “religious”? Would you leave it without a type or would you create a new type? That is a decision that is based on the business rules. In this particular business, ALL songs must have a type, so you would create a new type. Slide 10: Tell Me / Show Me – SONG has a TYPE (continued) Optionality (must or may?): Must every TYPE describe or classify a SONG? Can you have a TYPE with no SONGS under it? Point out that in the diagram, some TYPEs are not used to classify any SONGs Why have type called “New Age” when you don’t have any songs that can be classified under it? Why would you have the type at all? Possible answer: to prepare for future songs, since New Age seems to be an increasingly popular category.



Instructor Resource Guide Slide 11: Tell Me / Show Me – SONG has a TYPE (continued) Cardinality (how many?): Encourage discussion about the business rules and how they affect cardinality: Point out that in the business scenario, it is stated a SONG is classified under only one TYPE. That is the rule of this particular business. However, ask the class if it is possible for another business to classify a SONG under many TYPEs. Answer: quite possibly. Tell them that this would change the cardinality of the relationship. How many SONGs can fall under one TYPE? Again, the diagram and the business scenario indicate that a TYPE may be used to classify several SONGs. It’s a bit far-fetched to think of a business where a TYPE must apply to only one SONG, but ask the class if they can think of a scenario where this is possible. Encourage them to think of what is logically possible and what is probably unlikely. Slide 12: Tell Me / Show Me – Business scenario describing relationships: Point out that this statement describes the basic relationship between ORDER and CUSTOMER, but in order to fully capture the business rules, we need to revise the sentence to include optionality and cardinality. Slide 13: Tell Me / Show Me – CUSTOMER has ORDERs: Optionality (must or may?): Encourage discussion about the business rules and how they affect optionality: Must a CUSTOMER place an ORDER? Do you consider someone a CUSTOMER if he/she has not placed an ORDER? The diagram indicates that all customers have orders; therefore, someone who does not have an order is not a customer. Challenge the students to imagine another business where you could have a customer with no order. Possible answer: Some restaurants define a customer as anyone who enters the premises (uses the restroom, public phone, etc.). In this case, the optionality of the relationship will change to: Each CUSTOMER may place one or more ORDERs. Discuss the other end of the relationship: Must an ORDER be placed by a CUSTOMER, or can you have an ORDER that is not placed by any CUSTOMER? Can anyone in class think of a case where this could be true? Cardinality (how many?): How many ORDERs can one CUSTOMER place? Again, have them think of the business. In the given scenario, a CUSTOMER can place many ORDERs. Is it likely that in another business a CUSTOMER is allowed only one ORDER? Probably not in the food business. How many CUSTOMERs are responsible for a single ORDER? The scenario states that only one CUSTOMER is responsible for an ORDER. However, ask the class if they’ve ever eaten at a restaurant where they asked the waiter to split the payment for the bill between two or more credit cards. This would mean a different



Instructor Resource Guide cardinality for the relationship. Have them state it: Each ORDER must be placed by one or more CUSTOMERs. Slide 14: Tell Me / Show Me – A relationship can relate an entity to itself In section 4 we will see that MANAGER may be a subtype of EMPLOYEE. In order to fully capture the business rules, we need to revise the relationship to include optionality and cardinality: Each EMPLOYEE must be managed by one and only one EMPLOYEE. Each EMPLOYEE may manage one or more EMPLOYEEs. Slide 15: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 16: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 17: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 3 – ER Diagramming Conventions Lesson Slide 1: ER Diagramming Conventions Lesson Preparation No further lesson preparation information. What to Watch For Make sure students are naming both sides of the relationship and stating the optionality and cardinality. This will help students draw it in the next lesson. Get them accustomed to using “must/must be” or “may/may be” and “one and only one” or “one or more.” Also point out that an attribute may be mandatory or optional depending on the business and its rules. Give an example: an EMPLOYEE’s eye color may be optional in a restaurant business, but may be mandatory in a security organization. When naming attributes, also mention their datatypes (number, date, character, etc.) Make sure students understand that more than one relationship can exist between entities. Example: different relationships between person and class (attend, teach, write). Also watch out for the crow’s feet pointing the wrong way. It’s a common mistake that should be corrected early. You can also mention that ideally you’d like to draw the relationships so that the “crows fly south and east," but that this is not a strict requirement. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? People speak different languages… No instructor notes for this slide Slide 4: Why Learn It? How well did you do? After viewing the graphic and guessing the meaning of each sign, you can also use another example – international sign language. It’s another way for people to communicate without even talking out loud! Slide 5: Tell Me / Show Me – It is efficient to communicate information… No instructor notes for this slide Slide 6: Tell Me / Show Me – DJs on Demand: Clients, Events, and Types No instructor notes for this slide Slide 7: Tell Me / Show Me – ER Drawing Conventions Softbox: A four-sided visual element with rounded corners, used to represent an entity in an ERD



Instructor Resource Guide Slide 8: Tell Me / Show Me – Drawing Conventions Mention that any attribute that is part of the UID is always mandatory. So it is also acceptable to draw it with “#” and “*” before the name. Slide 9: Tell Me / Show Me – Drawing Conventions When viewing the graphic that shows the relationships, just talk through it but tell students that you will discuss the rules of how to draw relationships in more detail in the next lesson. Slide 10: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 11: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 12: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 3 – Speaking ERDish and Drawing Relationships Lesson Slide 1: Speaking ERDish and Drawing Relationships Lesson Preparation No further lesson preparation information. What to Watch For Make sure students are naming both sides of the relationship and stating the optionality and cardinality. This will help students draw it in the next lesson. Get them accustomed to using “must/must be” or “may/may be” and “one and only one” or “one or more.” Also point out that an attribute may be mandatory or optional depending on the business and its rules. Give an example: an EMPLOYEE’s eye color may be optional in a restaurant business, but may be mandatory in a security organization. When naming attributes, also mention their datatypes (number, date, character, etc.) Make sure students understand that more than one relationship can exist between entities. Example: different relationships between person and class (attend, teach, write). Also watch out for the crow’s feet pointing the wrong way. It’s a common mistake that should be corrected early. You can also mention that ideally you’d like to draw the relationships so that the “crows fly south and east,” but that this is not a strict requirement. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? ERDish: The language or statements used to describe relationships between entities in an entity-relationship diagram Give examples of languages that end with “ish” – English, Swedish (ask for other examples from the class – Finnish, Yiddish, etc.). Encourage students to think abstractly. Suggest “languages” such as “SCHOOLish” that would include such words as credits, TAs (teaching assistants), terms, primary, and secondary (include words specific to your institution). Slide 4: Tell Me / Show Me – View the following scene between… Play the animation once, and then feel free to run it again, this time pausing at certain points for discussion. For example: When the waiter gives the chef the list of orders – pause and ask the class, “Do you see a problem here?” (The waiter doesn’t really specify which food items go on which orders). Then continue playing and point out that now the waiter is confused as well, because he didn’t organize his food items according to orders either.



Instructor Resource Guide Slide 5: Tell Me / Show Me – ERDish is the language we use to state… When building the ERDish – it helps to draw a standard relationship on the board. You can use ORDER and ORDER ITEM to relate it to the animation, or whatever you are comfortable with. Slide 6: Tell Me / Show Me – The components of ERDish: Read your diagram on the board from left to right, pointing out the ERDish components or highlighting them in a different color. Slide 7: Tell Me / Show Me – The components of ERDish: Read your diagram on the board from right to left, pointing out the ERDish components or highlighting them in a different color. Slide 8: Tell Me / Show Me – The components of ERDish: Read your diagram on the board from left to right, and then right to left, pointing out the ERDish components or highlighting them in a different color. Stress the diagramming conventions: optionality by a solid (must) or dashed (may) line, cardinality by a single line (one and only one) or crow’s feet (one or more). Slide 9: Summary No instructor notes for this slide Slide 10: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 11: Summary – Practice Guide No instructor notes for this slide



Instructor Resource Guide SECTION 3 – Matrix Diagrams Lesson Slide 1: Matrix Diagrams Lesson Preparation The matrix diagram is a quick topic. This activity should take no more than 10 minutes, leaving 20 minutes for the quiz and 10 minutes for assessment. What to Watch For Note that if an entity is related to itself, a cell on the diagonal will also contain a relationship. Connections Go Over Activity: Photography Ask these questions of the class:

• Are the films developed in the same lab or in different labs? • Does the photographer develop any of his/her films? • Is a roll of film used on only one subject or on different subjects? • Are all the pictures on a roll of film taken under the same conditions or do they

vary? Although students may not know how to model the answers at this point, just tell them that these are examples of business rules that they will learn how to represent in the ERD. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? Matrix diagram: A grid-like drawing that can be used to discover and record relationships between entities in an entity-relationship model Sometimes when you have a lot of entities, it’s hard to know where to start defining relationships. What if you miss something? How do you make sure that you haven’t missed some combination of entities? Maybe there’s a relationship you’ve missed! We are going to learn another useful way for identifying relationships. Slide 4: Tell Me / Show Me – Business Scenario: Demonstrate how to draw a matrix diagram by creating a grid with a diagonal line running across it and filling top rows and left columns with the names of the entities – in this case, TRAVELER, COUNTRY, and LANDMARK. Slide 5: Tell Me / Show Me – Relationships discovered via the matrix… Point out that after using the matrix diagram, you should draw the relationships on the ERD to specify optionality and cardinality. Read the ERDish in the completed ERD and match it with what was listed in the matrix diagram.



Instructor Resource Guide Note that there are M:M relationships between TRAVELER and COUNTRY, and between TRAVELER and LANDMARK. Tell them that these are valid relationships, but they will be discussed more later. Slide 6: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 7: Summary – In this lesson you have learned how to: No instructor notes for this slide Slide 8: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 3 – Identifying Relationships Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Cardinality/ Degree A property of an end of a relationship between X and

Y, that describes how many of X is related to Y.

Relationship A connection or association between objects.

Optionality A property of an end of a relationship between X and Y, that describes whether X must be or may be related to Y.

Try It / Solve It 1. Read the given business scenario. Name the relationships between EMPLOYEE and

JOB. Include appropriate optionality and cardinality.

“We have a lot of employees who handle one or more different jobs. We’d like to keep track of who is working on which job. Although employees can help each other, a job is assigned to one employee and is the ultimate responsibility of that individual. All our employees have at least one job. However, there are jobs that are not yet assigned to anyone.”

Solution: Each EMPLOYEE must have (or handle, or be responsible for) one or more jobs. Each JOB may be the responsibility of (or assigned to) one and only one EMPLOYEE.

2. Read the given business scenario. Name the relationships between ORDER and

WAITER, including the cardinality and optionality.

“We assign our waiters to certain areas, except for our trainees, who just observe and are not responsible for taking any orders yet. A waiter takes the orders for the tables in his/her area. All areas have one assigned waiter. A customer places an order with a waiter. If the customer has a question or wants to make a change to the order, he/she needs to request this with the assigned waiter.”




Solution: Each WAITER may be assigned to (or handle, or take) one or more ORDERs. Each ORDER must be assigned to (or handled by, or taken by) one and only one WAITER.

3. Read the given business scenario. Name the relationships between PARENT and

CHILD. Include appropriate optionality and cardinality.

“At the end of each day, parents need to pick up their children at our day-care center. All children must be picked up by 6 p.m. A child may have two parents, but we need only one of them to come and pick up their child or their children. We cannot release a child to anyone but that child’s parents.”

Solution: Each PARENT may pick up one or more CHILDren. Each CHILD must be picked up by one and only one PARENT.

4. Read the given business scenario. Name the relationships between TEACHER and

STUDENT. Include appropriate optionality and cardinality.

“Some students request remedial help in certain subjects, such as math. We can assign a tutor who can work with the student after class. Some of our teachers agree to be tutors. If several students need tutoring in one subject, then we assign them to the same teacher. If a student needs tutoring in several subjects, then he/she will probably be assigned to several different tutors.”

Solution: Each TEACHER may tutor one or more STUDENTs. Each STUDENT may be tutored by one or more TEACHERs.

5. Draw two entities from your own experience (use colored pens and markers on hand).

Write down the relationships between these two entities, including cardinality and optionality. Share your entities with the class.

Solution: Have the class go through this exercise only if there is extra time. Verbalizing the diagram demonstrates understanding and creates a desire on the part of the student to think more deeply about what they are creating because they will be required to “share” later. If you do not have time to allow the “sharing,” you may want to collect the papers to observe the understanding of each student at this critical juncture. Presenting is much more public and an easier for which you can provide feedback.



Instructor Resource Guide SECTION 3 – ER Diagramming Conventions Lesson Vocabulary Directions: Identify the vocabulary word for the definition below. Softbox A four-sided visual element with rounded corners,

used to represent an entity in an ERD.

Try It / Solve It 1. Read the given business scenario. Draw the entities HAIRSTYLIST and CLIENT.

List the attributes associated with each entity and specify whether they are mandatory or optional. Identify the UIDs. Write out the relationship in English, including optionality and cardinality. Follow the diagramming conventions discussed.

“In our salon, we have a number of hairstylists. They are all salaried employees, so we keep a record of their first name, last name, address, phone number, social-security number, and salary. During the course of a day, a hairstylist may see several clients. On a slow day, a hairstylist may not work on anyone at all. We have several walk-in clients, and they each get assigned to one hairstylist. We just ask for their first name. We also have customers who call to make an appointment. When they do this, we ask for their first name, last name, and phone number. We also ask if they would like a specific hairstylist. If they have no preference, we assign one for them. Of course, they are allowed to switch to another hairstylist for their next visit to the salon. We are interested in tracking the daily appointments – which stylist works on which client during a given day.”

Solution: In some cases, there could be discussion about whether an attribute is mandatory or optional. Encourage this discussion and tell students that if it is not clear in the business scenario, they need to make assumptions. These assumptions should be documented so you can go back to the client later and confirm them. HAIRSTYLIST # id * first name * last name * address * phone number * social-security number




CLIENT #client number * first name o last name o phone number A HAIRSTYLIST may work on one or more CLIENTs. A CLIENT must be assigned to one and only one HAIRSTYLIST.

2. Read the given business scenario. Draw the entities BAND and MUSICIAN. List the

attributes underneath each entity. Specify whether they are mandatory or optional. Identify the UIDs. Write out the relationships in English, including optionality and cardinality.

“I am an agent for several musicians and bands. A musician may be a solo performer or may belong to a band. A band will always have one or more musicians in it (some musicians are a one-man band). However, a musician can belong to only one band. Since I schedule them for concerts and events, I need to keep track of certain information: the musician’s first name, last name, address, phone number, and hourly rate. If it’s a band, I need to know the band name in addition to the information I already keep for the member musicians. I’ve handled bands with the same name, so just to make sure I book the right band, I assign an ID to each one. The hourly rate for a band is the total of the hourly rates of its members.”

Solution: In some cases, there could be discussion about whether an attribute is mandatory or optional. Encourage this discussion and tell students that if it is not clear in the business scenario, they need to make assumptions. These assumptions should be documented so you can go back to the client later and confirm them. Why not have hourly rate as an attribute for a band? Answer: because it can be derived from the hourly rates of the members. BAND # band id * band name MUSICIAN # number * first name * last name * address * phone number * hourly rate




Each BAND must be composed of one or more MUSICIANs. Each MUSICIAN may belong to one and only one BAND.

3. Read the given business scenario. Draw the entities TEACHER and COURSE and CLASS. List the attributes under each entity, and specify if they are mandatory or optional. Identify the UIDs. Write out the relationships in English, including optionality and cardinality.

“We have several teachers at our school. A teacher can be assigned up to three classes per semester. If a teacher is on sabbatical, he/she doesn’t teach that semester. We keep a record of the teacher’s first name, last name, address, phone number, and email address.” “Our school offers many courses – such as Data Modeling, Introduction to SQL, Trigonometry, Physics, and Biology. Each course has a code. For example: Data Modeling would be DM001, Trigonometry would be TR004, etc. During each semester, a course may be taught in several classes – so there could be two classes of Physics, three classes of Biology, etc. Each class can be taught by only one teacher. We assign a unique ID for each class, and we also keep track of the day it is taught, the time, and the classroom.”

Solution: The exercise: TEACHER, COURSE, and CLASS deals with three entities. It is a bit more complicated but can be worthwhile for the faster students. Have them do this if there is time. TEACHER # teacher id * first name * last name * address * phone number * email address COURSE # code * description CLASS # id * day * time * classroom




Each TEACHER may be assigned one or more CLASSes. Each CLASS must be assigned to one and only one TEACHER. A COURSE may be offered through one or more CLASSes. Each CLASS must be an offering for one and only one COURSE.



Instructor Resource Guide SECTION 3 – Speaking ERDish and Drawing Relationships Lesson Vocabulary Directions: Identify the vocabulary word for the definition below. ERDish The language or statements used to describe

relationships between entities in an entity-relationship diagram.

Try It / Solve It 1. The goal of this practice is to read a relationship. Which text corresponds to the

diagram?

a. Each EMPLOYEE may be assigned to one or more DEPARTMENTs. Each DEPARTMENT must be responsible for one or more EMPLOYEEs.

b. Each EMPLOYEE must be assigned to one and only one DEPARTMENT.

Each DEPARTMENT must be responsible for one or more EMPLOYEEs.

c. Each EMPLOYEE must be assigned to exactly one DEPARTMENT. Each DEPARTMENT may be responsible for exactly one EMPLOYEE.

Solution: Option b. is the correct reading.

2. In the diagram for #1 identify the symbols for cardinality.

Solution: Crows foot and single toe foot 3. In the diagram for #1 identify the symbols for optionality.

Solution: Solid line (no dotted line exists)



Instructor Resource Guide 4. Read the relationship in the diagram below. Write the ERD statement for the

relationship.

Solution: Each camera may be used to take one or more photographs Each photograph must have been taken with one camera

5. Read each of the relationships in the model below. Write the ERD statement and your

thoughts on each relationship. Use your knowledge of people and towns.




Solution: • Each person must be born in one or more towns. • Each town may be birthplace of exactly one person. • Comment: Both sides seem to be of the wrong degree.

• Each person must be living in one or more towns. • Each town may be the hometown of one or more persons. • Comment: The first certainly has a wrong degree. The optionality seems wrong

as well.

• Each person may be visitor of one or more towns. • Each town must be visited by one or more persons. • Comment: The optionality of the second seems very likely, but is probably

wrong, depending on the definition of town. (Is it possible that a town could be visited by 0 persons? What if the town was formed yesterday by the government? Would they have visitors yet? No.

• Each person may be mayor of exactly one town. • Each town may be governed by (as mayor) exactly one person. • Comment: Both seem fine, except that if you need to keep historical information,

then both sides of the relationship must be “many.” Historical information is that which is tracked as it changes over time. In this case, a person may be mayor of one town this year, then of another town the next year. Although a town can have only one mayor at one time, it has different mayors over the years.



Instructor Resource Guide SECTION 3 – Matrix Diagrams Lesson Vocabulary Directions: Identify the vocabulary word for the definition below.

Matrix 1. A grid-like drawing that can be used to discover and record relationships between entities in an entity- relationship model

Try It / Solve It 1. Read the business scenario and review the ERD. Using the matrix diagram, make up

two or more possible relationships between PHOTOGRAPH and the other entities that make sense for the business.

“I am an amateur photographer. I own several cameras and am always taking pictures of different subjects. I am trying to keep track of which camera and type of film perform best under certain conditions – indoor light, outdoor light, etc. So when I have my films developed, I note down which camera I used. When the pictures come back, I note the subject and conditions. Each picture always features one subject. A subject could be a view, a person or group of persons, or an object or group of objects.” CAMERA PHOTOGRAPH SUBJECT CAMERA PHOTOGRAPH SUBJECT




Solution: The extra relationships could be Camera to Photograph A CAMERA may record one or more PHOTOGRAPHS A PHOTOGRAPH must be recorded by a CAMERA Photograph to Subject A SUBJECT may be captured in a PHOTOGRAPH A PHOTOGRAPH may capture a SUBJECT

2. Given the matrix diagram below, construct an ERD.

*************** Cross Country Runner

City For Race Race Type

Cross Country Runner

**************

City For Race

************

Race Type

***************

Solution:

*************** Runner

City For Race

Race Type Running Event

Runner ********* Run By City For Race *********

Held In

Race Type

********** Of a

Running Event

Participates In The Location Of

Used In *********




CITY FOR RACE

RACE TYPE

RUNNER

RUNNING EVENT

Participates in

Run by

The location of

Held in

Used in of a



Supertypes and Subtypes

2



What Will I Learn?

Objectives


• Define and give an example of a subtype

• Define and give an example of a supertype

• State the rules relating to entities and subtypes; give examples of each

• Apply the rules of supertype and subtype by evaluating the accuracy of ER diagrams that represent them

• Apply the rules of supertype and subtype and include them in a diagram when appropriate

3



Why Learn It?

Purpose

Supertypes and subtypes occur frequently in the real

world -- food orders (eat in, to go), grocery bags (paper,

plastic), payment type (check, cash, credit). You can

typically associate „choices‟ of something with

supertypes and subtypes. For example, „what do you

like on your sandwich‟ (mustard, mayonnaise, ketchup,

onions, tomatoes, sprouts, cucumbers, lettuce, other).

Understanding real world examples helps us

understand how and when to model them.

4



Tell Me / Show Me

Evaluating Entities

Often some instances of an entity have attributes and/or relationships which other instances do not have.

Imagine a business which needs to track payments from customers. Customers can pay by cash, by check or by credit card.

All payments have some common attributes: payment date, payment amount and so on. But only credit cards would have a “card number” attribute.

And for credit card and check payments we may need to know which CUSTOMER made the payment, while this is not needed for cash payments.

Should we create a single PAYMENT entity or three separate entities CASH, CHECK, and CREDIT CARD? And what happens if in the future we introduce a fourth method of payment?

PAYMENT

CASH

CHECK

CREDIT CARD

5



Tell Me / Show Me

Subdivide an Entity

Sometimes it makes sense to subdivide an entity into subtypes. This may be the case when a group of instances has special properties, such as attributes or relationships that exist only for that group. In this case, the entity is called a "supertype" and each group is called a subtype.

A subtype:

• inherits all attributes of the supertype

• inherits all relationships of the supertype

• usually has its own attributes or relationships

• is drawn within the supertype

• never exists alone

• may have subtypes of its own

• is also known as a "subentity“

Invertebrates are animals with no backbone (such as earth worms). Vertebrates have backbone and can be subdivided into birds, mammals, and reptiles etc.

ANIMAL

VERTEBRATE

INVERTEBRATE

ANIMAL SUPERTYPE

6



Tell Me / Show Me

Supertype Example

EXAM is a supertype of

QUIZ, MIDTERM, and

FINAL.

The subtypes have

several attributes in

common. These common

attributes are listed at the

supertype level. The same

applies to relationships.

Subtypes inherit all

attributes and

relationships of the

supertype entity.

STUDENT

BONUS

QUESTION

QUIZ

FINAL

* extra points for

optional paper

MIDTERM

* grade for oral presentation

EXAM

# number

* description

* weight

* date

*grade for written component

taken by

included in

includes

EXAM SUPERTYPE

take

7



Tell Me / Show Me

Always More Than One Subtype

When an ER model is complete,

subtypes never stand alone. In other

words, if an entity has a subtype, there

should always be at least a second

subtype. This makes sense. What use

would there be for distinguishing

between an entity and the single

subtype? This idea leads to the two

subtype rules:

Exhaustive: Every instance of the

supertype is also an instance of one of

the subtypes.

Mutually Exclusive: Every instance of

the supertype is of one and only one

subtype.

WALL COVERING

PAINT

WALLPAPER

FABRIC

OTHER

WALLCOVERING SUPERTYPE

At the conceptual modeling stage, it is

good practice to include an OTHER subtype to

make sure that your subtypes are exhaustive

-- that you are handling every instance of the

supertype.

8



Tell Me / Show Me

Subtypes Always Exist

Every entity can always be

subtyped. You can always make

up a rule to subdivide the

instances in groups.

But that is not the issue. The

reason for subtyping should

always be that there is a business

need to show similarities and

differences at the same time.

WALL COVERING

PAINT

WALLPAPER

FABRIC

OTHER

WALLCOVERING SUPERTYPE

9



Tell Me / Show Me

Correctly Identifying Subtypes

When considering supertypes and

subtypes, you can use three questions

to see if the subtype is correctly

identified:

(1) Is this subtype a kind of supertype?

(2) Have I covered all possible cases?

(exhaustive)

(3) Does the example fit into one and

only one subtype? (mutually

exclusive)

SNOWSPORT

SKI

SNOWBOARD

CROSS COUNTRY

OTHER

10



Tell Me / Show Me

Nested Subtypes

You can nest subtypes. For

ease of reading --

“readability” -- you would

usually show subtypes with

only two levels, but there is no

rule that would stop you from

going beyond two levels.

ANIMAL

VERTEBRATE

BIRD REPTILE

MAMMAL OTHER

INVERTEBRATE

NESTED ANIMAL SUPERTYPE

11



Tell Me / Show Me

Terminology


Subtype / Subentity

Supertype

Exhaustive

Mutually Exclusive

12



Summary



• Define and give an example of a subtype

• Define and give an example of a supertype

• State the rules relating to entities and subtypes, and give examples of each

• Apply the rules of supertype and subtype by evaluating the accuracy of ER diagrams that represent them

• Apply the rules of supertype and subtype and include them in a diagram when appropriate

13



Summary

Practice Guide

The link for the lesson practice guide can be found in

the course resources in Section 0.


Documenting Business Rules

2



What Will I Learn?

Objectives


• Define and compose a structural business rule

• Define and compose a procedural business rule

• Recognize that some business rules will require

programming

• Diagram business rules when they can be represented

in an ER model

3



Why Learn It?

Purpose

One of the primary goals of data modeling is to ensure that

all pieces of information that are required to run a business

are recognized.

Identifying and documenting business rules are keys to

checking your data model for accuracy and completeness.

It is important to recognize that not all business rules can be

represented in the ERD. Some business rules must be

implemented by programming.

4



Why Learn It?

Identify This Business

5



Tell Me / Show Me

Structural and Procedural Business Rules

Structural business rules indicate the types of information

to be stored and how the information elements interrelate.

Procedural rules are workflow or business process related.

Structural business rules can nearly always be

diagrammed in the ERD. Some procedural business rules

cannot be diagrammed, but must still be documented.

Many procedural business rules are related to time: event

A must happen before event B.

6



Tell Me / Show Me

Structural Rule Example

Structural business rules indicate

the types of information to be

stored and how the information

elements interrelate. Here are a

few examples:

All orders at a restaurant must be

handled by a staff member

(specifically, an order taker).

There is no self-service ordering

system.

All teachers at our school must

possess a valid teaching

certificate.

ORDER STAFF

TEACHER

# id

* name

* address

• teaching certificate

number

handled by

handle

Structural Business Rules

7



Tell Me / Show Me

Rule Discussion

What kinds of rules does a employer have that affect you?

• Each shift I work must be documented on a time card.

• Each shift must be supervised by a manager.

Our school has many business rules:

• Is it reasonable/effective for a class not to have a teacher

assigned?

• Is it reasonable/effective for two students to have the same

student id number or no student id number at all?

• Is it reasonable to schedule a teacher to teach a class if no

students are enrolled?

• Is it reasonable to allow students to come to school if they

are not enrolled in any (one or more) classes?

8



sdm_s04_l04_a01

Tell Me / Show Me

Procedural Rule Example

Procedural business rules are workflow or process related. Here are some examples:

Initial contact with the client from DJs on Demand must be made by the project manager.

Approval for travel requests to an event must be signed by the project manager for that event.

9



Tell Me / Show Me

Diagram Discussion

• Students must have studied algebra and geometry in

order to sign up for trigonometry. Could you represent

this in the ERD?

• How would you implement this with programming?

• If the student had taken the subjects, can you think of

an additional business rule that a school may want in

this scenario?

10



Tell Me / Show Me

Documenting Rules

In the process of developing a conceptual data

model, not all business rules can be modeled.

Some rules such as the two listed below must

be implemented by programming as processes

that interact with data:

(1) any employee whose overtime exceeds 10

hours per week must be paid 1.5 times the

hourly rate

(2) customers whose account balances are 90

days overdue will not be permitted to charge

additional orders

sdm_s04_l04_a02

11



Tell Me / Show Me

Terminology


Business rule

Procedural business rule

Structural business rule

12



Summary



• Define and compose a structural business rule

• Define and compose a procedural business rule

• Recognize that some business rules will require

programming

• Diagram business rules when they can be

represented in an ER model

13



Summary

Practice Guide





INSTRUCTOR NOTES

SECTION 4 – Supertypes and Subtypes Lesson Slide 1: Supertypes and Subtypes Connections Review the complete ERD for the DJ business. Point out the subtypes for EMPLOYEE. Slide 2: What Will I Learn? No instructor notes for this slide Slide 3: Why Learn It? No instructor notes for this slide Slide 4: Tell Me / Show Me – Evaluating Entities No instructor notes for this slide Slide 5: Tell Me / Show Me – Subdivide an Entity Subtype/ Subentity: Something an entity may be split into based on common attributes and/or relationships Supertype: A means of classifying an entity that has subtypes Slide 6: Tell Me / Show Me – Supertype Example Read the diagram as: Every QUIZ, MIDTERM, or FINAL is an EXAM (and thus has attributes such as description, weight, grade, and date). Conversely: Every EXAM is either a QUIZ, a MIDTERM, or a FINAL. Slide 7: Tell Me / Show Me – Always More Than One Subtype Exhaustive: Treating all parts or aspects without omission. Mutually exclusive: A relationship that presents choices which are unable to be true at the same time Slide 8: Tell Me / Show Me – Subtypes Always Exist No instructor notes for this slide Slide 9: Tell Me / Show Me – Correctly Identifying Subtypes No instructor notes for this slide Slide 10: Tell Me / Show Me – Nested Subtypes No instructor notes for this slide




Slide 11: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 12: Summary – Objectives Summarized No instructor notes for this slide Slide 13: Summary – Practice Guide No instructor notes for this slide




SECTION 4 – Documenting Business Rules Lesson Slide 1: Documenting Business Rules No instructor notes for this slide Slide 2: What Will I Learn?- Objectives No instructor notes for this slide Slide 3: Why Learn It?- Identify This Business “Implemented by programming” means that once the database is created, a programmer would write code that would enforce a business rule. Slide 4: Why Learn It?- Purpose “Implemented by programming” means that once the database is created, a programmer would write code that would enforce a business rule. Slide 5: Tell Me / Show Me – Structural and Procedural Business Rules Business rule: A formalized statement of the usual, customary, or generalized course of action or behavior for a business Structural business rule: A structural business rule indicates the types of information to be stored and how the information elements interrelate Procedural business rule: A business rule that is workflow or business process related. (e.g., A has to happen before B, and then C has to happen at the same time as D.) This is also called a process business rule Slide 6: Tell Me / Show Me – Structural Rule Example No instructor notes for this slide Slide 7: Tell Me / Show Me – Rule Discussion No instructor notes for this slide Slide 8: Tell Me / Show Me – Procedural Rule Example Ask students the question: What procedural business rule is evident from the animation? Answer: The project manager first works with the client to confirm the event. Then he assigns an event manager and a DJ to the event. Discussion: How do you represent this in the ER diagram? Can you? Answer: No, this is a rule that will have to be implemented by a computer program. Visualize a system where the partners can look up events and update them. The program could allow only the project manager to enter a new event and then assign the partners who will be working on it. Once the assignment is made, the system could send out an email




notification to the event manager and the DJ, giving them details about the event, the customer contact information, etc. Slide 9: Tell Me / Show Me – Diagram Discussion Could you represent this in the ERD? Answer: No. How would you implement this with programming? Answer: When a student tries to sign up online for the trigonometry class, a piece of code would “check” to see if that student had taken algebra and geometry. If the student had taken the subjects, can you think of an additional business rule that a school may want in this scenario? Answer: Student achieved a passing grade. Slide 10: Tell Me / Show Me – Documenting Rules Discussion: Why would you document this? Why would you document anything? Answers include: What if you leave the project? What if you don’t implement the database? The person who does implement the database will discover that the physical model may not address all the needs of the business because of situations like this! Important: most procedural rules will be implemented in the physical model by database check constraints, triggers or privileges, or by application code. In the conceptual model, the question is: can we draw it in the ERD, or must we document it in words? Slide 11: Tell Me / Show Me – Terminology No instructor notes for this slide Slide 12: Summary – Objectives Summarized No instructor notes for this slide Slide 13: Summary – Practice Guide No instructor notes for this slide




PRACTICE SOLUTIONS SECTION 4 – Supertypes and Subtypes Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Exhaustive Treating all parts or aspects without omission.

Supertype A means of classifying an entity that has subtypes.

Subtype/Subentity Something an entity may be split into based on

common attributes and/or relationships.

Mutually exclusive A relationship that presents choices that are unable to be true at the same time.

Try It / Solve It 1. Identify the supertype and subtype of the entity listed below. DISABILITY Visual Impairment Hearing Impairment Amputation Paralysis

Solution: DISABILITY = supertype Visual Impairment = subtype Hearing Impairment = subtype Amputation = subtype Paralysis = subtype




2. For each rule stated indicate if the rule is applicable to supertypes or subtypes.

__________ They have several attributes in common __________ They inherit all attributes and relationships of the entity __________ Never exists alone __________ Create one when a group of instances of an entity have special properties Solution: Subtypes Subtypes Subtype Supertype

3. Name three things you consider when considering supertypes and subtypes.

Solution: • Is this subtype a kind of supertype? • Have I covered all possible cases? (exhaustive) • Does the example fit into one and only one subtype? (mutually exclusive)

4. Find the incorrect subtypes in the illustration. Explain why you think the subtype is

incorrect. Adjust the model to improve it.

Solution: The subtypes for AUTOMOBILE are not mutually exclusive. A 4-DOOR VEHICLE could also be a SEDAN and/or a SPORT UTILITY VEHICLE. Suggestion for improvement: remove 4-door vehicle subtype. Consider making “number of doors” an attribute of the supertype. Add other nonoverlapping subtypes or an “OTHER” subtype. The subtypes of BUILDING are not exhaustive. Surely there are other BUILDINGs that are not a HOUSE. Add more subtypes or add an OTHER subtype. Some possible




subtypes of building are OFFICE, SCHOOL, and FACTORY. Ask students to name other examples of BUILDINGs that could be subtypes.

5. Read the following scenario and construct an ERD that contains at least two subtypes

of the entity PRODUCT. Show clearly which attributes belong to the entity supertype, and which belong to one of the subtypes. Identify a UID for the entity.

“Our shops sell several kinds of women’s clothing, including dresses, skirts and blouses. Of course each product has a name, a description and a price. Oh, and sizes too: all products have a waist size. Dresses and skirts have a hem length but blouses don’t. Dresses and blouses have a chest size; skirts don’t.”

Solution: This is tricky because the subtype attributes overlap. For example, hem length is an attribute of two of the three subtypes (two of four if you include an OTHER subtype). Either the hem length can be an attribute of both subtypes DRESS and SKIRT, or hem length can be an attribute of the supertype, with a null value for instances of BLOUSE.




SECTION 4 – Documenting Business Rules Lesson Vocabulary Directions: Identify the vocabulary word for each definition below. Structural business rule A structural business rule indicates the types of

information to be stored and how the information elements interrelate.

Business rule A formalized statement of the usual, customary, or generalized course of action or behavior for a business.

Procedural business rule A business rule that is workflow or business process related. (e.g., A has to happen before B, and then C has to happen at the same time as D.) This is also called a process business rule.

Try It / Solve It 1. Members of your design team have been working with the local hospital to develop a

data model for their need to store information about patients, the patient's room number, the patient's doctor, drug prescriptions given, and specific drug information.

However, they all went on vacation and left you to figure out the model. They also failed to give you any of their documentation other than the entities and attributes illustrated here. Instead of going back to the hospital, which could reflect poorly on your company, you’re going to have to think about everything you know about hospitals! Your task is to generate a list of business rules you think were used to arrive at the information shown here. Use your imagination. List 10 structural rules, 5 procedural rules, and 2 programmatic rules (rules to be addressed by computer applications in the future). State each rule as a single sentence. Based on your set of business rules, draw the ERD.




Solution: • Structural Rules:

A patient is someone who is admitted to the hospital. Each room assignment must include the building number and room number. Each room may be occupied by one or more patients. A physician must have a valid license number. Each drug must be prescribed by a physician. Each drug prescribed must have a label showing label number, dosage, treatment duration, and expiration date. The drug code, name, and cost must be recorded for all drugs. Each prescription must have a number and date. Each physician may be assigned to more than one patient. Each patient must have an assigned physician.

• Procedural Rules: Changes to prescriptions can be made only by licensed physicians. Patients cannot refill prescriptions without a physician's signature. Physicians cannot remove drug labels. Patients cannot change hospital rooms without a physician's recommendation. Nurses cannot reassign patients without physician approval.

• Programming Rules: Drugs costs are billed at current cost at the time of patient discharge. Physician fees may reflect additional costs associated with patient complications, additional patient requests, etc.






Relationship Transferability

2



What Will I Learn?

Objectives


• Understand the difference between transferable and

nontransferable relationships

• Describe and give an example of relationship

nontransferability

• Illustrate nontransferable relationships on ERDs

3



Why Learn It?

Purpose

Once a class has been allocated to a teacher, can that class

later be transferred to another teacher, possibly in mid-

semester? Usually yes, because if not, what would we do if the

first teacher becomes sick?

Some health clubs allow memberships to be transferred from

one person to another, but other health clubs don’t. This

business rule is normally determined by what is most efficient

and most profitable for the club.

4



Tell Me / Show Me

Relationship Review

Let’s review a simple relationship

between SONG and TYPE.

Optionality:

Can you have a TYPE that does

not classify any SONG?

Must every SONG have a TYPE?

Cardinality:

How many SONGs can be

classified under one TYPE?

How many TYPEs can a SONG

have?

Transferability:

Can a SONG be changed from

one TYPE to another TYPE?

SONG

# id

* title

o duration

o artist

TYPE

# code

* description

classified by

classify

SONG and TYPE

5



Tell Me / Show Me

Nontransferable Relationships

Transferable: A STUDENT being

allowed to move from one STUDY

GROUP to another. There is a

relationship between STUDENT and

STUDY GROUP that is transferable.

Nontransferable: A STUDENT can be

issued a RECEIPT for paying tuition

fees, taking a certification exam, or

purchasing items at the bookstore.

Once a RECEIPT has been issued, it

cannot be transferred to another

STUDENT. If it was issued in error, it

would have to be cancelled, and

another RECEIPT would have to be

written up. The relationship between

STUDENT and RECEIPT is

nontransferable.

STUDENT STUDY GROUPjoin

have

RECEIPT STUDENTissued to

issued

Transferable Relationship

Nontransferable Relationship

A nontransferable relationship

is represented with the

diamond on the relationship.

6



Tell Me / Show Me

More Nontransferable

Relationships

Ownership of a POEM belongs with

its AUTHOR. Authorship is a

relationship that cannot be moved to

another person.

In the DJ business, an EVENT is

owned by the CLIENT. If there are

questions about outstanding

payments on an EVENT, that

CLIENT cannot transfer

responsibility to another person.

He/she can designate a

representative, but ultimate

ownership still belongs with the

original CLIENT.

POEM AUTHOR

EVENT CLIENT

written by

the writer of

owned by

the owner of

7



Tell Me/ Show Me

Terminology:

Key terms in this lesson include:

Transferable

Nontransferable

8



Summary



• Understand the difference between transferable and

nontransferable relationships

• Describe and give an example of relationship

nontransferability

• Illustrate nontransferable relationships on ERDs

9



Summary

Practice Guide




Relationship Types

2

Relationship Types


What Will I Learn?

Objectives


• Recognize and give examples of a one-to-one

relationship

• Recognize and give examples of a one-to-many relationship

• Recognize and give examples of a many-to-many relationship

• Recognize redundant relationships and remove them from the ERD

3

Relationship Types


Why Learn It?

Purpose

Can one PERSON own many DVDs, or only one ?

Can one DVD be owned by many PERSONs?

As we refine and improve our model, we want to make sure

our entity relationships correctly model our business rules.

Remember, you can avoid future costly mistakes by thinking

through the details early on.

4

Relationship Types


Tell Me / Show Me

One-to-Many (1:M) Relationships

The various types of 1:M

relationships are most common in

an ER Model. You have seen

several examples already.

Relationship Types

1:M

EMPLOYEEDEPARTMENTwork for

has

1:M Relationship

5

Relationship Types


Tell Me / Show Me

Many-to-Many (M:M)

Relationships

The various types of M:M

relationships are common,

particularly in a first version of an

ER model. In later stages of the

modeling process, most M:M

relationships, and possibly all, will

disappear.

Relationship Types

M:M

STUDENT TEACHERlearn from

educate

M:M Relationships

6

Relationship Types


Tell Me / Show Me

One-to-One

Relationships For

Roles

Usually you will find just

a few of the various

types of 1:1

relationships in every

ER model.

Mandatory at one end of

the 1:1 relationship

commonly occurs when

roles are modeled. See

the school model.

Relationship Types

1:1

PERSONTEACHER

STUDENT

acting as

role of

acting as

role of

1:1 Relationships

7

Relationship Types


Tell Me / Show Me

One-to-One

Relationships For

Process

1:1 relationships (of

all three variations)

also occur when

some of the entities

represent various

stages in a

process.

EXAM ANSWER KEY

RECIPE DISH

evaluated with

for

the basis for

the result

1:1 Process Relationships

8

Relationship Types


Tell Me / Show Me

Redundant RelationshipsA redundant relationship can be derived from another relationship in the model.

In the example on the left, you can derive the relationship from PERSON to COUNTRY from the other two relationships, and you should remove them from the model -- as indicated on the left.

However, be careful of concluding that a relationship is redundant based on the structure alone. Read the relationships to check. The ERD on the right does not reflect a redundant relationship.

the birthplace

of

COUNTRY

TOWN

PERSON

located

in

location of

hometown

living born in

COUNTRY

TOWN

PERSON

location of

located in

hometown

of

living in

hometown

ofliving in

9

Relationship Types


Tell Me / Show Me

Terminology


Many-to-many (M:M)

One-to-many (1:M)

One-to-one (1:1)

Redundant

10

Relationship Types


Summary



• Recognize and give examples of a one-to-one

relationship

• Recognize and give examples of a one-to-many

relationship

• Recognize and give examples of a many-to-many

relationship

• Recognize redundant relationships and remove them

from the ERD

11

Relationship Types


Summary

Practice Guide




Resolving Many-to-Many Relationships

2



What Will I Learn?

Objectives


• Identify attributes which belong to many-to-many

relationships

• Demonstrate the steps to resolve a many-to-many

relationship using an intersection entity

• Identify the UID of an intersection entity and represent it in

the entity relationship diagram

3



Why Learn It?

Purpose

This lesson will help you complete your model -- you may need

to create new entities or new relationships based on the

business needs.

It will also help you define the scope of your data model -- you

only model what is of importance to the business.

4



Tell Me / Show Me

Relationship Hiding an Attribute

In the DJ business, each

PARTNER may be assigned to

work on one or more EVENTs.

Each EVENT may be a job for one

or more PARTNERs.

When an EVENT PLANNER, a DJ,

or a PROJECT MANAGER works

on an EVENT, we want them to

record the status of the job.

Which entity would the attribute

"status" belong to?

PARTNER

# id

* first name

* last name

EVENT PLANNER

* expertise

DJ

* specialty

MANAGER

o authorized

expense limit

EVENT

# id

* name

* date

o description

* cost

work on

worked on

by

EVENT and PARTNER

5



Tell Me / Show Me

Resolution of a M:M Relationship

A third entity is needed to resolve the M:M relationship.

This is called an "intersection" entity.

sdm_s05_l03_a01

6



Tell Me / Show Me

Intersection Entity

An intersection entity

– JOB ASSIGNMENT

– has been added,

including the status

attribute.

The original M:M

relationship has

become two 1:M

relationships.

What would be the

UID of the

intersection entity?

PARTNER

# id

* first name

* last name

EVENT PLANNER

* expertise

DJ

* specialty

MANAGER

o authorized

expense limit

EVENT

# id

* name

* date

o description

* cost

JOB ASSIGNMENT

o status

responsible

for

the source of

for for

JOB ASSIGNMENT

7



Tell Me / Show Me

Barred Relationships

The unique identifier

(UID) of the

intersection entity

often comes from the

originating

relationships and is

represented by the

bars. In this case, the

relationships from the

originating entities to

the intersection entity

are called "barred"

relationships.

PARTNER

# id

* first name

* last name

EVENT PLANNER

* expertise

DJ

* specialty

MANAGER

o authorized

expense limit

EVENT

# id

* name

* date

o description

* cost

JOB ASSIGNMENT

o status

responsible

for

the source of

for for

JOB ASSIGNMENT

8



Tell Me / Show Me

M:M Resolution

Example TV Shows

Each TV show may be

watched by one or more

persons.

Each person may watch

one or more TV shows.

TV SHOW PERSONwatched by

watch

Resolution of M:M

PERSONTV SHOW

VIEWING

RECORD

for for

on on

TV SHOW

9



Tell Me / Show Me

M:M Resolution

Example Cleaning

Services

Each company may

provide one or more

cleaning services.

Each cleaning service

may be provided by one

or more companies.

CLEANING

COMPANY

CLEANING

SERVICE

provide

provided by

Resolution of M:M

CLEANING

COMPANY

CLEANING

SERVICE

CLEANING

SCHEDULE

forfor

onon

CLEANING SERVICES

10



Tell Me / Show Me

Terminology


Barred relationship

Intersection entity

11



Summary



• Identify attributes which belong to many-to-many

relationships

• Demonstrate the steps to resolve a many-to-many

relationship using an intersection entity

• Identify the UID of an intersection entity and represent it

in the entity relationship diagram

12



Summary

Practice Guide




Understanding CRUD Requirements

2



What Will I Learn?

Objectives


• Create ER models that reflect all business rules

gathered during the interview process

• Identify the create, retrieve, update, and delete (CRUD)

requirements of the business

• Validate your ER model by performing a CRUD analysis

3



Why Learn It?

Purpose

The ERD is the conversation tool between the consultant and

the client. It is also the guideline for the DBA who will

eventually build the database.

You need a way to check that you haven’t missed any entities

or relationships in your data model. It’s like taking a list of

books to the school book store. You also want to make sure

that you haven’t modeled anything that the business does not

require. CRUD analysis will help you do this.

4



Tell Me / Show Me

CRUD Analysis

A good way to validate an ERD is to do a CRUD analysis on

it. CRUD is an acronym for create, retrieve, update, delete.

These are the four basic operations that a database allows.

Part of checking a data model for completeness and

accuracy is making sure that all the CRUD functions

specified by the business scenario and the business rules

are represented in the ERD.

5



Create Operation

Keywords to look for in the client interviews, business

scenarios and so on are INPUT, ENTER, LOAD, IMPORT,

RECORD, and CREATE. These all indicate that a record is

created in the database at this time. Review the

requirements for these keywords. Does your data model

account for all these functions?

Tell Me / Show Me

6



Retrieve Operation

Keywords to look for are VIEW, REPORT, BRING UP,

PRINT, FIND, READ and LOOK UP. These all point to

retrieving information from the database. Review the

requirements for these keywords. Does your data model

account for all these functions?

Tell Me / Show Me

7



Tell Me / Show Me

Update Operation

Keywords to look for are CHANGE, MODIFY, ALTER and

UPDATE. These all point to updating information that is

already in the database. Review the requirements for these

keywords. Does your data model account for all these

functions?

8



Tell Me / Show Me

Delete Operation

Keywords to look for are DISCARD, REMOVE, TRASH,

PURGE and DELETE. These all point to deleting information

that is already in the database. Review the requirements for

these keywords. Does your data model account for all these

functions?

9



CRUD Validation

Performing a CRUD analysis on your data model helps you

check for scope and completeness:

If you have a business function that has no entity to CRUD

against, then your data model may be incomplete.

Similarly, if you have entities in your ERD that are not

touched by any CRUD (there is no business function that

creates, retrieves, updates, or deletes from it), then you

may not need that entity in your model.

Tell Me / Show Me

10



Tell Me / Show Me

Terminology


Consultant

Functions

CRUD analysis

11



Summary



• Create ER models that reflect all business rules gathered

during the interview process

• Identify the create, retrieve, update, and delete (CRUD)

requirements of the business

• Validate your ER model by performing a CRUD analysis

12



Summary

Practice Guide




Artificial, Composite and Secondary UIDs

2



What Will I Learn?

Objectives


• Define the different types of unique identifiers (UIDs)

• Define a candidate UID and explain why an entity can

sometimes have more than one candidate UID

• Analyze business rules and choose the most suitable

primary UID from the candidates

• Recognize and discuss the issues of identification in the

real world

3



Why Learn It?

Purpose

The unique identifier (UID) is very important in relational

databases.

It is the value or combination of values that enables the

user to find that one unique item among all the rest.

Identifying just the right attribute, combination of attributes,

and/or relationships is a skill that any database designer

must master. The unique identifier is the way to find your

record in a file, a particular card in a deck of cards, your

package in a warehouse, and a specific piece of data in a

database.

4



Tell Me / Show Me

Simple UIDs vs.

Composite UIDs

A UID that is a single

attribute is a simple UID.

However, sometimes a

single attribute is not

enough to uniquely

identify an instance of an

entity. If the UID is a

combination of attributes,

it is called a composite

UID.

DEPARTMENT

# code

* name

CONCERT TICKET

# date of performance

# seat number

Simple Unique

Identifier

Composite Unique

Identifier

5



Tell Me / Show Me

Artificial UIDs

Artificial UIDs are those that

don’t occur in the natural world

but are created for purposes of

identification in a system.

People are not born with

“numbers,” but a lot of systems

assign unique numbers to

identify people: student numbers,

customer IDs, etc.

A shoe has a color, a size, a

style, but no truly descriptive

“number.” However, a shoe store

will assign unique numbers to

each pair of shoes so they can

be uniquely identified.

SHOE

* color

* size

* style

SHOE

# shoe ID

* color

* size

* style

Create an

artificial UID

6



Tell Me / Show Me

Artificial UID Example

How can we uniquely

identify a STUDENT?

Could we use a combination

of first name and last name?

Only if we are sure that the

combination is unique.

Often, it is simpler and more

straightforward to create an

artificial attribute and make

it the unique identifier.

A UID can be both artificial

and composite.

STUDENT

* first name

* last name

* address

STUDENT

# student ID

* first name

* last name

* address

Create an artificial UID

7



Tell Me / Show Me

UIDs from Barred

Relationships

Sometimes the UID is a

combination of an attribute

and a relationship.

What is the UID of

ACCOUNT? Is it artificial?

Is it composite?

Two people could have the

same bank account number,

but at different banks.

Bank to bank transfers

always need the bank

routing number in addition to

the bank account number.

ACCOUNT

# number

* balance

* date opened

BANK

# number

* name

* location

at

have

8



Tell Me / Show Me

UID from Barred Relationship

Intersection Entity

As we’ve seen before, the

resolution of a M:M relationship

often results in barred

relationships from the

intersection entity to the original

ones.

In this example, the UID of PLAY

LIST ITEM comes from EVENT

and SONG. The bars on the

relationships tell you this.

PLAY LIST ITEM

o comments

EVENT

# id

* cost

* name

* date

o description

SONG

# id

* title

o artist

o duration

for for

have on

9



Tell Me / Show Me

Artificial UID Intersection Entity

It is possible for an intersection entity to

use an artificial attribute as the UID,

instead of the barred relationships to

the originating entities.

Each MANUFACTURER may produce

one or more PRODUCTs (shoes,

shirts, jeans, etc.). Each PRODUCT

may be produced by one or more

MANUFACTURERs (Nike shoes,

Adidas shoes, Levi’s jeans, etc.).

CATALOG ITEM

# number

* price

MANUFACTURER

# number

* name

PRODUCT

# code

* description

CATALOG ITEM resolves this many-to-many relationship. An item in a

catalog can be uniquely identified by the manufacturer number and the

product code. The relationships are not barred, because an artificial UID –

catalog number – has been created instead.

10



Tell Me / Show Me

Candidate UIDs

Sometimes there is more than one possible UID.

For example, when you order a product from a commercial website, you will usually be assigned a unique customer code and also asked to enter your e-mail address.

Each of these uniquely identifies you, and each could be chosen as the UID. These are both candidate UIDs.

Only one of the candidate UIDs is chosen as the actual UID. This is called the primary UID. The other candidates are called secondary UIDs.

11



Tell Me / Show Me

Candidate UIDs (continued)

Student ID has been chosen as the

primary UID in both of these STUDENT

entities.

The first entity has one secondary UID,

while the second has two secondary UIDs

(one of which is composite).

STUDENT

# student ID

(#) badge number

* first name

* last name

* address

One Primary UID

One Secondary UID

STUDENT

# student ID

(#1) badge number

(#2-1) first name

(#2-2) last name

* address

One Primary UID

Two Secondary UIDs

12



Tell Me / Show Me

Identification: Database vs. Real

World

Unique identifiers make it possible

for us to distinguish one instance of

an entity from another. As you will

see later, these become primary

keys in the database. A primary key

allows you to access a specific

record in a database.

In the real world, however, it is

sometimes not so easy to

distinguish one thing from another.

sdm_s07_l02_a01

13



Tell Me / Show Me

Terminology


Artificial UID

Candidate UID

Composite UID

Primary UID

Secondary UID

Simple UID

UID

14



Summary



• Define the different types of unique identifiers (UIDs)

• Define a candidate UID and explain why an entity can

sometimes have more than one candidate UID

• Analyze business rules and choose the most suitable

primary UID from the candidates

• Recognize and discuss the issues of identification in the

real world

15



Summary

Practice Guide


course outline.


Normalization and First Normal Form

2



What Will I Learn?

Objectives


• Define the purpose of normalization in database models

• Define the rule of First Normal Form in the normalization

process

• Determine if an entity conforms to the rule of First Normal

Form

• Convert an entity to First Normal Form if needed

3



Why Learn It?

Purpose

Think about storing your friends’ phone numbers in three different places:

your address book, your cell phone, and a sheet of paper that you have

taped to your refrigerator. It’s a lot of work if a friend changes his/her phone

number. You have to change it in your address book, cell phone, and the

sheet of paper taped to your refrigerator.

What happens if data is stored in more than one place in a database? What

if someone changes the information in one place and not the other? How do

you know which information is correct?

Normalization is a process to eliminate these kinds of problems.

Your goal as a database designer is to "store information in one

place and the best place“. Following the rules of normalization helps

you achieve this goal.

4



Tell Me / Show Me

First Normal Form (1NF)

First Normal Form requires that there

be no multivalued attributes.

To check for 1NF, validate that each

attribute has a single value for each

instance of the entity.

There are many classrooms in a

school building, so it is a repeating

attribute. This is a violation of 1NF.

If an attribute has repeating values,

create an additional entity and relate it

to the original entity with a M:1

relationship.

SCHOOL BUILDING

# code

* name

* address

o classroom

SCHOOL BUILDING

# code

* name

* address

CLASSROOM

# number

* floor

* size

The classroom attribute

will have multiple values.

This entity is not in First

Normal Form.

CLASSROOM is now its own entity.

All attributes have only one value per instance.

Both entities are in First Normal Form.

SCHOOL BUILDING 1NF

the location

of

located

in

5



Tell Me / Show Me

1NF Violations

Examine the entities on the right.

Are there any multivalued

attributes?

CLIENT

# number

* first name

* last name

o event

SHOPPING

MALL

# id

* name

* address

* store name

* store floor

TEAM

# id

* name

* player

LEAGUE

# number

* name

belong to

made up of

1NF Violations

1)

2)

3)

6



Tell Me / Show Me

1NF Solutions

When all the attributes in

an entity are single-

valued, that entity is said

to be in First Normal

Form.

EVENT

# id

* name

CLIENT

# number

* first name

* last name

* event

belong to

own

STORE

# name

* floor

SHOPPING

MALL

# id

* name

* address

•store name

store floor

located in

house

TEAM

# id

* name

* playerbelong to

made up of LEAGUE

# number

* name

PLAYER

# number

* name

o position

have

belong to

1NF Solutions

1)

2)

3)

7



Tell Me / Show Me

Terminology


Normalization

First Normal Form (1NF)

Redundancy

8



Summary



• Define the purpose of normalization in database

models

• Define the rule of First Normal Form in the

normalization process

• Determine if an entity conforms to the rule of First

Normal Form

• Convert an entity to First Normal Form if needed

9



Summary

Practice Guide




Second Normal Form

2

Second Normal Form


What Will I Learn?

Objectives

In this lesson, you will learn how to:

• Define the rule of Second Normal Form in the


• Examine a nonnormalized entity and determine which

rule (or rules) of normalization are being violated

• Apply the rule of Second Normal Form to resolve a

violation in the model

3

Second Normal Form


Why Learn It?

Purpose

Your goal as a database designer is to “store information in

one place and the best place.”

Following the rules of normalization helps you achieve this

goal.

When organizing information such as your friends’ phone

numbers and addresses, you want to make sure that you

store it in the appropriate place -- such as a personal

address book. If you store a friend’s address in your recipe

box, for instance, you may not find it until the next time you

look up that recipe.

Normalization is a process to eliminate these kinds of

problems.

4

Second Normal Form


Tell Me / Show Me

Second Normal Form Example

Examine the entity PRODUCT

SUPPLIER. The UID is a combination of

Supplier number and Product number.

What about the Supplier Name attribute?

If one supplier supplies 5 different

products, what happens if the supplier

name changes ?

The name would need to be changed in 5

instances of the entity. What if some of

them were changed, but not others? What

would be the correct value for the supplier

name?

PRODUCT SUPPLIER

# supplier number

# product number

* purchase price

* supplier name

5

Second Normal Form


Tell Me / Show Me

Second Normal Form Description

Second Normal Form requires that any non-UID attribute

be dependent on the entire UID.

This means that all attributes that are not part of the

entity’s UID should be dependent on the whole UID. This

specifically applies to entities that have a UID that is

composed of more than one attribute or a combination of

attribute(s) and relationship(s).

6

Second Normal Form


Tell Me / Show Me

Second Normal Form Bar Relationship

The same ACCOUNT numbers exist at different BANKs so

the relationship is part of the UID. This is represented by the

bar on the relationship.

ACCOUNT

# number

* balance

* date opened

BANK

# number

* name

located in

the location

for

7

Second Normal Form


Tell Me / Show Me

Second Normal Form

Violation

In this ERD, however, the

attribute bank location is

misplaced. It depends ONLY

on the BANK number.

This is a violation of Second

Normal Form.

What would happen if a bank’s

location changed? All the

accounts at that bank would

need to be changed.

ACCOUNT

# number

* balance

* date opened

* bank location

BANK

# number

* name

8

Second Normal Form


Tell Me / Show Me

Second Normal Form Song Example

The DJ is responsible for preparing the collection of

songs to be played at each event. Each SONG can

be played at more than one EVENT, and each

EVENT will use more than one SONG. Let’s look at

how the DJ prepares the play list.

9

Second Normal Form


Tell Me / Show Me

Modified DJ ERD

What is wrong with this

diagram?

Answer: The attributes

duration and event date

are misplaced. Duration

depends solely on SONG,

and event date depends

solely on EVENT.

This is a violation of

Second Normal Form.

PLAY LIST ITEM

o comments

o duration

* event date

EVENT

# id

* cost

* name

o description

SONG

# id

* title

o artist

10

Second Normal Form


Tell Me / Show Me

Terminology


Second Normal Form (2NF)

11

Second Normal Form


Summary



• Define the rule of Second Normal Form in the


• Examine a nonnormalized entity and determine which


• Apply the rule of Second Normal Form to resolve a


12

Second Normal Form


Summary

Practice Guide




Third Normal Form

2

Third Normal Form


What Will I Learn?

Objectives


• Identify transitive dependencies in a data model

• Define the rule of Third Normal Form in the


• Examine a non-normalized entity and determine which


• Apply the rule of Third Normal Form to resolve a


3

Third Normal Form


Why Learn It?

Purpose

Your goal as a database designer is to "store information in one place and

the best place." Following the rules of normalization helps you achieve this

goal.

You may want to enter different kinds of information for a friend in your

personal address book: phone number, address, name of school or place of

work. If you have several friends who go to the same school, and you enter

the school’s street address along with each of them, you would not only be

duplicating data but causing potential problems -- for instance, if the school

moved and changed its address, you would have to go back and change it

everywhere!

Normalization is a process to eliminate these kinds of problems.

4

Third Normal Form


Tell Me / Show Me

Third Normal Form Rule

The rule of Third Normal Form (3NF) states that no

non-UID attribute can be dependent on another

non-UID attribute.

Third Normal Form prohibits transitive

dependencies. A transitive dependency exists when

any attribute in an entity is dependent on any other

non-UID attribute in that entity.

Think of the kind of information you'd like to store

about your CD collection. Does information about

the store where you bought the CD belong in the

same entity?

If the store address changed, you would have to

change the information on all the CDs that were

bought at that store.

CD

# id

* title

* producer

* year

o store name

o store address

Third Normal

Form Violation

5

Third Normal Form


Tell Me / Show Me

Third Normal Form Transitive

Dependency

The store address is dependent on the

CD number, which is the UID of the CD

entity. So this entity is in 1NF and 2NF.

But store address is also dependent on

store name, which is a non-UID

attribute.

This is an example of a transitive

dependency and a violation of Third

Normal Form.

The correctly normalized model is

shown here: create a second entity

STORE, with a relationship to CD.

CD

# id

* title

* producer

* year

o store name

o store address

CD

# id

* title

* producer

* year

Third Normal

Form Violation

STORE

# number

* name

* address

contained in

contains

Third Normal

Form

6

Third Normal Form


Tell Me / Show Me

Third Normal Form

Example

Consider a system that

tracks information about

cities -- size, population,

mayor, and so on.

The first model shows an

entity that includes state

information. Although state

is an attribute of city, state

flower is really an attribute of

state.

The second model, with a

new entity STATE, is in

Third Normal Form.

CITY

# id

* name

* size

* population

* mayor

* state

* state flower

CITY

# id

* name

* size

* population

* mayor

STATE

# id

* name

* flower

in

have

Third Normal

Form Violation

Third Normal

Form

7

Third Normal Form


Tell Me / Show Me

Third Normal Form Second

Example

In this example, assume the

following business rule: each

employee can have one

partner.

This model violates Third

Normal Form because partner

birth date is an attribute of

partner, not of EMPLOYEE.

Another way of stating Third

Normal Form: non-UID

attributes can’t have attributes

of their own.

EMPLOYEE

# id

* name

* address

* birth place

o partner name

o partner birth date

DEPARTMENT

# number

* name

* budget

part of

composed

of

Third Normal

Form Violation

8

Third Normal Form


Tell Me / Show Me

3NF Second Example

Solution

This model supports Third

Normal Form because partner

birth date is an attribute of

partner, not of EMPLOYEE.

The 1:1 relationship is optional

on the EMPLOYEE end

because some employees will

not have partners. It is

mandatory on the PARTNER

end because information about

a partner is tracked only if that

person is a partner of one and

only one EMPLOYEE.

part ofEMPLOYEE

# id

* name

* address

* birth place

DEPARTMENT

# number

* name

* budgetcomposed

of

Third Normal

FormPARTNER

# name

* birth date

have

the dependent of

9

Third Normal Form


Tell Me / Show Me

Terminology


Third Normal Form (3NF)

Transitive dependency

10

Third Normal Form


Summary



• Identify transitive dependencies in a data model

• Define the rule of Third Normal Form in the normalization

process

• Examine a nonnormalized entity and determine which rule

(or rules) of normalization are being violated

• Apply the rule of Third Normal Form to resolve a violation

in the model

11

Third Normal Form


Summary

Practice Guide




Arcs

2

Arcs


What Will I Learn?

Objectives


• Define the term "constraint" as it applies to data

modeling

• Identify an exclusive OR relationship in a business

scenario

• Diagram an arc constraint to represent an exclusive OR

relationship

• Distinguish between the use of an arc and a subtype in

the data model

3

Arcs


Why Learn It?

Purpose

Arcs in data modeling help designers clarify an exclusive

OR across relationships. The more explicitly you can define

the client's requirements, the more accurate your final

implementation will be.

4

Arcs


Tell Me / Show Me

What is a Constraint?

Every business has restrictions on which attribute

values and which relationships are allowed.

These restrictions are called constraints. They may

refer to a single attribute of an entity, or to

relationships between entities.

We already know about several kinds of constraint,

for example: every EMPLOYEE must work in one

and only one DEPARTMENT.

In this lesson we will see another kind of constraint:

an exclusive OR constraint.

5

Arcs


Tell Me / Show Me

Exclusive OR

Relationships

Mutually exclusive

relationships (sometimes

called “exclusive OR”

relationships) often exist.

For example:

A billboard is an advertising

space that can feature a

movie, a product, or a

public announcement. It

may contain advertising

about only one of these at a

time. Each “feature” has its

own characteristics or

attributes.

feature

feature

feature

featured

on

featured

on

featured

on

BILLBOARD

# number

* size

* location

MOVIE

# title

o opening date

PRODUCT

ADVERTISEMENT

# name

PUBLIC

ANNOUNCEMENT

# message

6

Arcs


Tell Me / Show Me


The DJ business has a mutually

exclusive relationship between EVENT

and VENUE.

sdm_s07_l03_a01

7

Arcs


Tell Me / Show Me

Representing Exclusive

OR Relationships in the

ERD

Arcs are a way to represent

mutually exclusive

relationships in the ERD.

The arc represents the

exclusive OR relationship --

each EVENT must be held

at one PRIVATE HOME or

must be held at one PUBLIC

SPACE, but not both.

EVENT

# id

* cost

* name

* date

o description

PRIVATE HOME

# id

* address

o comments

PUBLIC SPACE

# id

* address

* rental fee

o comments

the venue for the venue for

held at held at

8

Arcs


Tell Me / Show Me

Arcs

• An arc always belongs to one

entity.

• Arcs can include more than two

relationships.

• Not all relationships of an entity

need to be included in an arc.

• An entity may have several arcs.

• An arc should always consist of

relationships of the same

optionality:

• All relationships in an arc must

be mandatory or all must be

optional.

• Relationships in an arc may be

of different degree, although

this is rare.

USER

LIST ITEM

LIST

is referred to

referring

to

container ofis

referred

to

referring

tocontained in

9

Arcs


Tell Me / Show Me

Arcs (continued)

Examine the following example.

10

Arcs


Tell Me / Show Me

Arcs, Supertypes, and Subtypes

Arcs can sometimes be drawn as

supertypes or subtypes.

EVENT

# id

* cost

* name

* date

o description

VENUE

# id

* address

o comments

PRIVATE HOME

o accessibility

feature?

PUBLIC SPACE

* rental fee

held at

the venue for

11

Arcs


Arcs, Supertypes, and

Subtypes (continued)

Supertypes and subtypes

can sometimes be drawn

as arcs.

The supertype PARTNER

in the DJ model is

represented as an arc in

this diagram.

Tell Me / Show Me

12

Arcs


Tell Me / Show Me

Terminology


Arc

Constraint

Exclusive OR relationship

Mutually exclusive relationship

13

Arcs


Summary



• Define the term "constraint" as it applies to data

modeling

• Identify an exclusive OR relationship in a business

scenario

• Diagram an arc constraint to represent an exclusive OR

relationship

• Distinguish between the use of an arc and a subtype in

the data model

14

Arcs


Summary

Practice Guide




Hierarchies and Recursive Relationships

2



What Will I Learn?

Objectives


• Define and give an example of a hierarchical

relationship

• Identify the UIDs in a hierarchical model

• Define and give an example of a recursive relationship

• Represent a recursive relationship in an ERD given a

scenario

• Construct a model using both recursion and

hierarchies to express the same conceptual meaning

3



Why Learn It?

Purpose

Often, roles are organized by hierarchy -- at work (manager,

crew chief, front-counter clerk, food preparers), or in school

(headmaster or principal, assistant headmaster or assistant

principal, teachers, staff). Hierarchical data is very common.

Understanding it will help you model:

• Business organizational charts

• Building structures

• Family trees

and many other hierarchies found in the real world.

4



Tell Me / Show Me

Relationships in an Organizational Chart

An organizational chart can be represented

by this data model. What are the UIDs for

each entity?

Entry-Level

Employees

Manager

Director

President

reporting to

reporting to

reporting to

the

manager

of

the

manager

of

the

manager

of

President

Director

Manager

Entry Level Employee

5



Tell Me / Show Me

Another Relationship

Example

What are the UIDs for each

entity in this ERD? (Notice the

barred relationships.)

ROOM

# id

located

the location of

located

the location of

located

the location of

SUITE

#* number

o tenant

FLOOR

#* number

BUILDING

#* id

* name

* address

6



Tell Me / Show Me

Hierarchy Versus

Recursive Relationship

Both of these models

represent all employees.

The one on the left is a

hierarchical structure. The

one on the right uses a


Which one do you think is

better? ENTRY-LEVEL EMPLOYEE

# badge number

* name

o salary

MANAGER

# badge number

* name

o salary

* budget

PRESIDENT

# badge number

* name

o salary

* car plan

DIRECTOR

# badge number

* name

o salary

* bonus plan

EMPLOYEE

# badge number

* first name

* job

o salary

o budget

o bonus plan

o car planmanaged

by

the manager

of

7



Tell Me / Show Me

DJs on Demand

Business Scenario

In the DJ model, the

project manager has

overall responsibility for

an event and manages

the other employees

(event planner, DJ)

working on the event.

We chose to represent

the hierarchy with a


PARTNER

# id

* first name

* last name

EVENT PLANNER

* expertise

DJ

* specialty

MANAGER

o authorized expense report

OTHER

supervise

supervised by

8



Tell Me / Show Me

Automobile

Manufacturing

Business Scenario

For an automobile

manufacturing

organization, consider all

elementary parts,

subassemblies,

assemblies, and

products as instances of

an entity called

COMPONENT. The

model can be created as

a simple recursive

relationship.

Model Bill of Materials data as a many-

to-many recursive relationship:

• Each COMPONENT may be a

part of one or more

COMPONENTS.

• Each COMPONENT may be

made up of one or more

COMPONENTS.

COMPONENT

# identifierA part of

Made up of

9



Tell Me / Show Me

Terminology


Hierarchal relationship

Recursive relationship

10



Summary



• Define and give an example of a hierarchical relationship

• Identify the UIDs in a hierarchical model

• Define and give an example of a recursive relationship

• Represent a recursive relationship in an ERD given a

scenario

• Construct a model using both recursion and hierarchies to

express the same conceptual meaning

11



Summary

Practice Guide




Modeling Historical Data

2



What Will I Learn?

Objectives


• Identify the need to track data that changes over time

• Construct ERD models that incorporate elements of “data over time”

• Identify the UID of an entity that stores historical data; explain and

justify the choice of UID

• Construct a conceptual model based on a given business scenario

• Apply the rules of entity-relationship diagramming to create an ERD

that reflects the business rules

• Present and interpret the data model to an audience

• Compose written documentation to accompany the oral presentation

and an ERD

3



Why Learn It?

Purpose

How tall were you at age 5? How tall were you at age 10? How tall are you

right now? If your parents wrote this down when you were young, they

were keeping track of historical data. Most businesses need to track some

historical data. This helps them find trends and patterns that can be the

basis for business innovations or process improvements.

For example, rental history of a movie is useful to a video store. It tells

managers which movies are popular and which should be moved to the

back shelf.

Can you think of an application for a pharmaceutical company, a

commercial dairy or bakery, or a seafood-processing plant? What historical

data would each want to keep and why?

4



Tell Me / Show Me

Model Data Over Time

When is it necessary to model data over time?

Ask your client:

• Is an audit trail required?

• Can attribute values change over time?

• Can relationships change over time?

• Do you need to produce reports on older data?

• Do you need to keep previous versions of the

data? If so, for how long?

5



Tell Me / Show Me

Data Over Time Example

An organization needs to keep data about

employees’ salaries. All employees are

paid weekly.

Initially, the following EMPLOYEE entity

was modeled.

Additional requirements now specify that

the organization needs to keep a historical

record of how and when employees’

salaries have changed during their

employment.

EMPLOYEE

# id

* first name

* last name

* weekly salary amount

* salary start date

6



Tell Me / Show Me

Model Salary Changes

To model salary changes over time, add a SALARY

HISTORY entity.

for

having

The UID of the SALARY HISTORY entity is the related EMPLOYEE id

and the salary start date.

EMPLOYEE

# id

* first name

* last name

SALARY HISTORY

# salary start date

o salary end date

* weekly salary amount

7



Tell Me / Show Me

Model Rental Over Time

A jewelry store rents pieces

(necklaces, bracelets and so on)

to movie stars for special

occasions, such as award

ceremonies or movie premieres.

They would like to track the

rental history of a jewelry piece.

The following ER model will only

track the current renter of a piece

of jewelry.

How would you revise the

relationship to track history?

JEWELRY PIECE

# code

* description

* rental rate

* insured value

MOVIE STAR

# id

* first name

* last name

rented by

renting

8



Tell Me / Show Me

Resolve M:M

The relationship between

JEWELRY PIECE and

MOVIE STAR should be

revised to a M:M, which is

then resolved with an

intersection entity

RENTAL HISTORY.

What is the UID of

RENTAL HISTORY?

JEWELRY PIECE

# code

* description

* rental rate

* insured value

MOVIE STAR

# id

* first name

* last name

rented by

renting

The M:M relationship is resolved with an

intersection entity.

JEWELRY PIECE

# code

* description

* rental rate

* insured value

MOVIE STAR

# id

* first name

* last name

RENTAL HISTORY

* date

* date returned

for

on

for

on

9



Tell Me / Show Me

Barred Relationship

The UID of RENTAL

HISTORY is date rented and

the UID of JEWELRY PIECE

(shown by the barred

relationship).

JEWELRY PIECE

# code

* description

* rental rate

* insured value

MOVIE STAR

# id

* first name

* last name

RENTAL HISTORY

# date

* date returned

for

on

for

on

10



Tell Me/ Show Me

Terminology

Historical data

Audit trail

11



Summary



• Identify the need to track data that changes over time

• Construct ERD models that incorporate elements of “data over time”

• Identify the UID of an entity that stores historical data; explain and

justify the choice of UID

• Construct a conceptual model based on a given business scenario

• Apply the rules of entity-relationship diagramming to create an ERD

that reflects the business rules

• Present and interpret the data model to an audience

• Compose written documentation to accompany the oral presentation

and ERD

12



Summary

Practice Guide




Presentation of the ERD to the Client

2



What Will I Learn?

Objectives


• Share and translate the ER model with the client in an

engaging way

• Use non-technical terms when describing the ER model

to the client

• Document design revisions requested by the client

3



Why Learn It?

Purpose

Continue to apply what you’ve learned and simulate a real-

world situation.

Most clients will not be familiar with data-modeling

techniques and terminology. Using their own business terms

and examples will help your client understand your

presentation and model.

4



Tell Me / Show Me

Tell Your Story

Your presentation should be organized and well prepared. It

is a good idea to assign roles and responsibilities to

different group members for each part of the presentation.

This presentation provides you an opportunity, as a

consultant, to check your assumptions of the business

requirements with the Director. “Tell the story” that the client

told you during your initial meeting while showing and

explaining the ERD.

5



Tell Me / Show Me

Use a Simple Vocabulary

Consultants should not use technical terms with the client such

as unique identifier, attribute, or entity. Clients do not know

what these things are. You can, and should, show the client

how to read relationships on the diagram. Once the client

understands how to read the diagram, they should be able to

help verify if the relationship is correct.

This is also a time for you to make sure that you are gathering

all the data the client requires for each of the entities. For

example, "Is there any other information that you would like to

know about your adopters besides name and address?"

6



Tell Me / Show Me

Terminology


Consultant

Client

7





• Share and translate the ER model with the client in an

engaging way

• Use nontechnical terms when describing the ER model to the

client

• Document design revisions requested by the client

Summary

8



Summary

Practice Guide




Modeling Change: Time

2



What Will I Learn?

Objectives


• Distinguish between using date as an attribute and DAY

as an entity in a data model, depending on business

requirements

• Solve the problem of keeping characteristics of a date by

constructing a model that uses DAY as an entity

• Identify at least three time-related constraints that can

result from a time-sensitive model

• Define and give an example of conditional non-

transferability in a time-constrained model

3



Why Learn It?

Purpose

Time plays a role in many business models.

For example: A book may be checked out from

the library several times, by different people, or

by the same person. The model may need to

track a history of borrowing for a book. Think

about a florist-supply company or a city police

department. How could time play a role in their

information needs?

4



Why Learn It?

Purpose (continued)

Historical data is often used by businesses to find trends

that can point the way to more efficient ways of doing

business. Modeling time in a business allows such data to

be captured.

Reports provide information that can be derived from the

data. A well-designed report can provide valuable

information that the business can use to improve its

operations.

5



Entity DAY vs. Attribute Date

Consider the entity PURCHASE. You

would include an attribute “date” if you

wanted to know when the item was

purchased. However, if we wanted to

identify trends -- such as when do

people buy coats vs. bathing suits vs.

sneakers? We may want to know the

temperature during that time.

What is wrong with the revised entity

shown here?

Tell Me / Show Me

PURCHASE

# id

* date

* quantity

* unit price

PURCHASE

# id

* date

* quantity

* unit price

* high temperature

* low temperature

6



Entity DAY vs. Attribute Date

(continued)

Remember Third Normal Form: a

non-UID attribute cannot have

attributes of its own.

Because high and low

temperature are attributes of the

date, we need a separate entity

DAY.

Can you think of a useful report

that the business could produce

from this data?

Tell Me / Show Me

PURCHASE

# id

* quantity

* unit price

DAY

# date

* high temperature

* low temperature

made on

the time for

7



Entity DAY vs. Attribute Date (continued)

Tell Me / Show Me

8



Tell Me / Show Me

Time-related Constraints

Be aware of constraints that can result from

the need to track dates and times. Here is an

example:

Consider a school fair that features several

booths. The manager signs up volunteers to

work different shifts at different booths. A

booth is staffed by only one volunteer at a

time. Some volunteers can work for several

hours; others can work fewer hours

depending on their free time. The schedule

has to be determined in advance, so that the

manager knows which times are not covered

by any volunteers.

sdm_s10_l01_a01

9



Time-related Constraints

(continued)

Here is a selection of time-related

constraints that need to be

considered for this model:

The obvious one: shift “end time”

must be later than shift “start

time.”

Shift times may not overlap. The

“start time” for a shift for a

volunteer may not be between

any “start time” and “end time” of

another volunteer on the same

booth. The same is true for the

“end time.”

Tell Me / Show Me

SHIFT ASSIGNMENT SCHEDULE

# date

# start time

* end time

BOOTH

# id

* name

VOLUNTEER

# number

* name

for

worked by

for

work on

10



Conditional Non-transferability

The “start time” for a shift may be

updated to a later time, unless the

shift has already begun.

The “start time” for a shift may be

updated to an earlier time, unless

the shift has already begun.

You probably would not allow a

shift to be reassigned to another

volunteer or another booth, unless

the shift had not yet started. This

is an example of conditional non-

transferability.

Tell Me / Show Me


# date

# start time

* end time

BOOTH

# id

* name

VOLUNTEER

# number

* name

for

worked by

for

work on

11



Conditional Non-transferability

(continued)

Non-transferability: a SHIFT

ASSIGNMENT cannot be changed

to another BOOTH (or to another

VOLUNTEER). Nontransferable

relationships are represented by a

diamond in the ERD.

Conditional non-transferability: a

SHIFT ASSIGNMENT can

sometimes be changed – in this

case, if the shift has not yet started.

These relationships cannot be

represented in the diagram, but

must still be documented.

Tell Me / Show Me


# date

# start time

* end time

BOOTH

# id

* name

VOLUNTEER

# number

* name

for

worked by

for

work on

12



Tell Me / Show Me

Terminology


Time-related constraint

Non-transferability

Conditional non-transferability

13





• Distinguish between using date as an attribute and DAY

as an entity in a data model, depending on business

requirements

• Solve the problem of keeping characteristics of a date

by constructing a model that uses DAY as an entity

• Identify at least three time-related constraints that can

result from a time-sensitive model

• Define and give an example of conditional non-

transferability in a time-constrained model

Summary

14



Summary

Practice Guide

The link for the lesson practice guide can be found in the course resources in Section 0.


Modeling Change: Price

2



What Will I Learn?

Objectives


• Solve the business requirement of tracking changes in

price or values by constructing a model that uses a

historical entity

• Describe the meaning of journaling/logging

• Identify the business need for journaling/logging and

construct a model that addresses this requirement

3



Why Learn It?

Purpose

Historical prices are important when looking for trends,

determining appreciation or depreciation value of items, or

getting a refund for an item purchased in the past at a

previous price.

Many businesses track history of change, who changed it,

when it was changed, and so on.

Example: if a student’s grade is changed, it is useful to

record when it was changed, the old grade, the new grade,

and who changed it.

4



Tell Me / Show Me

The Importance of Price Changes

Changes in price are often an important consideration when modeling business requirements. Some examples would be:

The stock market: Prices are changing by the second and you are watching the reader board, wondering when to buy and when to sell. What factors would you consider?

sdm_s10_l02_a01

5



Tell Me / Show Me

The Importance of Price Changes (continued)

The fuel industry: Why would you want to track the price changes in fuel if you are thinking of buying a car or during the winter when you heat your home?

Construction businesses: Why are price changes important to a contractor of a five-year bridge-construction project?

6



Tell Me / Show Me

The Good Old Days

The prices of products change over

time. Some go up.

sdm_s10_l02_a02

7



Tell Me / Show Me

Can You Believe What I Paid for It?


time. Some go down.

sdm_s10_l02_a03

8



Tell Me / Show Me

What’s the Price Today?


time. Some go up and down.

sdm_s10_l02_a04

9



Model Historical Price

It is often useful to have

information on past prices.

The model shown here tracks

the historical price of a

product.

PRODUCT

# id

* name

PRICE

# start date

o end date

* price

with

of

Tell Me / Show Me

10



Tell Me / Show Me

Historical Price Changes

Consider what happens when you

return an item to a store. You

purchased the item at a certain price,

but it has gone on sale since then.

sdm_s10_l02_a05

11



Tracking Price Changes

Businesses often need to

keep a record of price

changes. In this model, we

assume that each

PURCHASE is of only one

product.

The price that was paid can

be found by matching the

purchase date between the

start date and the end date

of PRICE.

Tell Me / Show Me

PRODUCT

# id

* name

PRICE

# start date

o end date

* price

with

of

PURCHASE

# id

* purchase date

* quantity purchased

between

12



Tell Me / Show Me

Other Data Changing Over Time

We’ve seen that price changes over

time. There are other types of

information that can also change, for

different business reasons.

sdm_s10_l02_a06

13



Journaling

Whenever a system allows a

user to modify or remove

particular information, the

question should be asked if

the old values need to be kept

on record. This is called

"logging" or "journaling." This

is often an issue when the

information is financial or of a

sensitive nature, such as a

student grade change.

Tell Me / Show Me

PAYMENT

# id

* date paid

* amount

AMOUNT MODIFICATION

* old amount

* modified by

# date modified

of

with

made by

for

14



Journal Content

A journal usually consists of both

the modified value and the

information about who did the

modification and when it was

done. This extra information can,

of course, be expanded if you

wish.

Tell Me / Show Me

EMPLOYEE

# id

* first name

* last name

* salary amount

SALARY CHANGE

# date modified

* old salary amount

* modified by

for

with

15



Tell Me / Show Me

Terminology


Appreciation

Depreciation

Journaling and / or logging

16





• Solve the business requirement of tracking changes in

price or values by constructing a model that uses a

historical entity

• Describe the meaning of journaling/logging

• Identify the business need for journaling/logging and

construct a model that addresses this requirement

Summary

17



Summary

Practice Guide

The link for the lesson practice guide can be found in the course resources in Section 0.


Adding the Time Element to an ERD

2



What Will I Learn?

Objectives


• Apply the rule of using DATE as an entity successfully

• Modify an ERD to accommodate new design requirements

• Identify and design possible reports that can be produced

from the data; explain how the information from these

reports could be useful to the business

3



Why Learn It?

Purpose

Historical data is often used by businesses to find trends

that can point the way to more efficient ways of doing

business. Modeling time in a business allows such data to

be captured.

Reports provide information that can be derived from the

data. A well-designed report can provide valuable

information that the business can use to improve its

operations.

4



Tell Me / Show Me

Business Scenario

View how the director of the animal shelter provides new business requirements.

sdm_s10_l03_a01

5





• Apply the rule of using DATE as an entity successfully

• Modify an ERD to accommodate new design requirements

• Identify and design possible reports that can be produced from

the data; explain how the information from these reports could

be useful to the business

Summary

6



Practice Guide



Summary