Chapter 1 Overview of Database Concepts

Dr. Chen, Business Database Systems 1

BMIS441

• Read syllabus thoroughly and understand all policy – Attendance, Assignments– Quizzes, EXAMS– Seat chart etc.– MIS Career (see Bb)

• Methodology vs. Technology• Text books

Dr. Chen, Business Database Systems

Comments and Suggestions

A great teacher at summarizing concepts and is really dedicated to his job and loves what he does

At the beginning of the semester I felt that the rules of the class were a little extreme as far as grading and attendance went, yet as the year went on and i understood what was expected I felt that these expectations were reasonable. I feel that if they were explained better at the beginning of the semester I would have had less anxiety in relevance to the course.

Dr. Chen is a great professor. Loved his class.

I really enjoyed the course including both Dr. Chen's style of teaching and humor.

I fell that Dr. Chen really summarized the material well and showed the class how to apply the concepts learned in class to use. I fell like he did a good job making sure all key concepts were understood. I respected the fact that he set up individual meetings with all groups to talk about how they felt the class was going and how it could be improved, outside of class. It showed a lot about Dr. Chen's character


About SQL …

I thought this blog post was fun… and informative about some of the latest trends.http://blog.sqlizer.io/posts/sql-43/

http://blog.sqlizer.io/posts/sql-43/


Chapter 1Overview of Database Concepts

Jason C.H. Chen, Ph.D.Professor of MIS

School of Business, Gonzaga UniversitySpokane, WA 99258 USA

[email protected]


What is Information ?

DATA

Information is refined data.

INFORMATION

What is 80/20 rule?How to apply it to this scenario?


What is Information ?

DATA INFORMATION

80% of information/

valuable output

Trivial many (80%)? or

Vital few (20%)?

Other business example?


Data vs. Information

• Users really want is– Information

i What users can learn from the datavhow to satisfy their best customersvhow to allocate their resources most efficiently,vhow to minimize losses


Objectives of the MIS

Deliver the right informationto the right people,at the right time,with the right form.

Ultimately, MIS should improve the workers’ productivity.

who has what information about whom and when, where, and how will all be decided in the process of building an information system.


Objectives

• Define database terms• Identify the purpose of a database management

system (DBMS)• Explain database design using entity-relationship

models and normalization• Explain the purpose of a Structured Query

Language (SQL)• Understand how this textbook’s topics are

sequenced and how the two sample databases are used


A Relationship Between the Organization and the DataBase

OrganizationalIS Resources:

PictureOr

Model

OldState

NewState

Activities

DataBaseManagement

SystemsCorrespond with the processing of the events

(Add, modify, delete, …)

Transactions

D.B.

Information must be:

User

Events

1. Hardware2. Software3. Data4. Procedures5. People

1. Time: Timely, 2. Content: Accurate, relevant, and verifiable.3. Form: Presented in a useable form.

TM 0-10


A Relationship Between the Organization and the DataBase

OrganizationalIS Resources:1. Hardware2. Software3. Data4. Procedures5. People

PictureOr

Model

OldState

Events

NewState

Activities

DataBaseManagement

Systems D.B.

Transactions

(Add, modify, delete, …)Correspond with the processing of the events

Information must be:1. Time: Timely, 2. Content: Accurate, relevant, and verifiable.3. Form: Presented in a useable form.

User

TM 0-11


Questions

• Is MS/Access or Oracle (SQL/Server or IBM DB2) a data base?

• Y/N


Types of Data Processing

• Two types of data processing– File-based data processing

• e.g., applications developed by Java– Data-based data processing

• e.g, applications developed by Oracle or MS/Access)


Three file processing systems at a Furniture Company

Duplicate Data

What is the main problem in the

company’s processing systems?


Database Management System

??? Databasecontainingcentralized

shared data

Application#1

Application#2

Application#3


Database Management System

DBMS manages data resources like an operating system manages hardware resources

DBMS Databasecontainingcentralized

shared data

Application#1

Application#2

Application#3

What are the advantages of employing Data-based Data Processing?


Traditional File Processing

ProductSales rep

Supplier

Data Files

Purchasing System

Sales order processing

system

Product

Applications

Name, item#, description...

Name, item#, description...


Database Management Systems

Product

Sales rep

Supplier

Database

DatabaseManagem ent

System s

PurchasingSystem

Salesorder processing

system


Database Terminology

• Database – an organized collection of logically related data files

• Database management system (DBMS) – software used to create and interact with the database


Database Components• Character

– Basic unit of data– Can be a letter, number, or special symbol

• Field– A group of related characters– Represents an attribute or characteristic of an entity– Corresponds to a column in the physical database

• Record– A collection of fields for one specific entity– Corresponds to a row in the physical database

• File– A group of records about the same type of entity


• Break


Relational Database Terms• Entity: an object about which you want to store data• Table, column, row

– Flat file, attribute (or field), record• Relationships: links that show how different records are

related• Key Fields: establish relationships among records in

different tables• Five main types of key fields:

– primary keys– candidate keys– surrogate keys– foreign keys– composite keys


Primary Keys vs. Candidate Keys

• Primary key– Value must be unique for each record– Serves to identify the record– Present in every record– Can’t be NULL– Should be numeric

• Candidate key – Any field that could be used as the primary key– Should be a unique, unchanging numeric field


Surrogate Keys

• Surrogate key: created to be the record’s primary key identifier when no suitable primary key exists

• Surrogate key has no real relationship to the record to which it is assigned, other than to identify the record uniquely

• Developers configure the database to generate surrogate key values automatically

• In an Oracle database, you can automatically generate surrogate key values using a sequence

• Surrogate keys are always numerical fields, because the database generates surrogate key values automatically by incrementing the previous value by one


Foreign Keys• Foreign key: a field in a table that is a primary key in

another table• Foreign key creates a relationship between the two tables• Foreign key value must exist in the table where it is a

primary key


Composite Key

• Composite key: a unique key that you create by combining two or more fields

• Usually comprised of fields that are primary keys in other tables

ORDER_ID PRODUCT_ID ORDER_QUANTITY100 1 2100 2 2200 2 2200 1 1

Composite Key


Structured Query Language (SQL)

• Data sublanguage • Used to:

– Create or modify tables– Add data to tables– Edit data in tables– Retrieve data from tables

• ANSI and ISO standards


Data Models• A data model is a collection of concepts for

describing data.

CUSTOMER ORDER

• Three database models– Hierarchical– Network– Relational


Entity-Relationship Model (E-R Model)

• Used to depict the relationship that exists among entities

• The following relationships can be included in an E-R model:– One-to-one– One-to-many– Many-to-many


E-R Model Notation Examples

Figure 1-3 E-R Model notation examples

Please note that the name of entity should be singular even it contains multiple instances


One-to-One Relationship

• Each occurrence of data in one entity is represented by only one occurrence of data in the other entity

• Example: Each order has just one invoice and each invoice is assigned to just one order

ORDER INVOICE


One-to-Many Relationship

• Each occurrence of data in one entity can be represented by many occurrences of the data in the other entity

• Example: A class has only one instructor, but each instructor can teach many classes

Class Instructor


Many-to-Many Relationship• Data can have multiple occurrences in both

entities• Example: A student can take many classes,

and each class is composed of many students

• Can not be included in the physical database

Class Student


In-Class Exercise

• Work on – “JustLee” database and its “Cardinality”– “Customers” and “Orders” Entities

See file of “2. Customers_Orders (JLDB_Referential_Integrity)-out.pdf” on handout folder


ISBN Title Publication Date Cost Retail Category Publishe

r Contact Author

8843172113 Database Implementation

04-JUN-03 31.40 55.95 Computer American Publishing

Davidson T.Peterson



Davidson J.Austin



Davidson J.Adams

1915762492 Handcranked Computers


Davidson W.White



Davidson L.White

6522489652 Meaningful Accounting

25-MAY-08 41.60 85.00 Accounting Articulate Publishing

Brown M.Kane



Brown S. Little

Q: Can we create/enter the data base on the following table immediately?

BOOKS tableneed to update multiple times to maintain its data integrity


Problem Solving for Modeling a Database Project

Business ProblemStudy and Analyze w/Team

???

IMPLEMENTATION


Problem Solving for Modeling a Database Project

Business ProblemStudy and Analyze w/Team

ER or other Model

Normalized Forms(3NF)

User interview & Integrated Model

Normalization

IMPLEMENTATION


JustLee Example E-R Model


Figure 1-5 JustLee Books’ table structures after normalization


Figure 1-5 JustLee Books’ table structures after normalization

Correction (one of the cpk and fk)

Revised Version on ORDERITEMS Table


Processes from 1NF 2NF 3NF

Category Contact

Computer Davidson

Accounting Brown

ISBN Title Publication Date Cost Retail Category Publisher







ISBN Author

8843172113 T.Peterson

8843172113 J.Austin

8843172113 J.Adams

1915762492 W.White

1915762492 L.White

6522489652 M.Kane

6522489652 S. Little

ISBN Title Publication Date Cost Retail Category Publisher Contact Author



Davidson T.Peterson



Davidson J.Austin



Davidson J.Adams


21-JUN-05 21.80 25.00 Computer Amercian Publishing

Davidson W.White


21-JUN-05 21.80 25.00 Computer Amercian Publishing

Davidson L.White



Brown M.Kane



Brown S. Little

Category Code Category

10 Computer

50 Accounting

fk(foreign key)

We will learn all detailed processes in the main text (ch.4)

Now, how many times are needed to maintain its data integrity (UPDATE)


Databases Used in this Textbook – JustLee Books Database

• Assumptions– No back orders or partial shipments– Only U.S. addresses– Completed orders are transferred to the annual

SALES table at the end of each month to enable faster processing on the ORDERS table


Study all tables in the JustLee Books Database (JLDB)

• Primary key• Candidate key• Surrogate key• Foreign key• Composite key


Topics of the Text

• The first half of the text will focus on creating a database

• The second half of the text will focus on querying or retrieving data from a database


System Response TimeDepends on ...

• the speed of the network• the size of the database• the way the database is used …• a personal database running on a server

might handle 10 users making database transactions at the same time before becoming overloaded.


SQL, SQL*Plus, and PL/SQLLanguage or Tool Description

SQL A command language for communication with theOracle 10/11Server from any tool or application. OracleSQL contains many extensions.

SQL*Plus An Oracle tool that recognizes and submits SQL andPL/SQL statements to the Server for execution andcontains its own command language.

PL/SQL An Oracle Procedural Language for writing applicationlogic and manipulating data outside the database.

SQL*Plus ServerBuffer

SQL and PL/SQLScripts

Terminal


HW• Do Hands-On Assignments (p.21)• Class Exercise #1• HW: #3, 5 and #10 (ER-M)• Draw with Visio (or Word) and print a

hardcopy• You should read the pptx file and chapter 1 (up to

page 6) of Oracle 11g to get basic concepts about database and DBMS.

• Figures 1-4 and 1-5 should be studied thoroughly.


Installing Personal Oracle11g

• I created a “Discussion Questions” on the Bb for you to share (or post question) your experience on installation of Oracle 11g. Please participate and it will be also your part of class performance.

• • Please note that if your computer with 64-bit operating

system such as Windows 7, you can’t use the DVD to install Oracle since it is for 32-bit OS. Rather you need to download 64-bit Oracle 11g from the Oracle site (www.oracle.com) or type in keyword search of “Oracle 11g download”.


Summary

• A DBMS is used to create and maintain a database• A database is composed of a group of interrelated

tables• A file is a group of related records; a file is also

called a table in the physical database• A record is a group of related fields regarding one

specific entity; a record is also called a row• A record is considered unnormalized if it contains

repeating groups


Summary (continued)

• A record is in first-normal form (1NF) if no repeating groups exist and it has a primary key

• Second-normal form (2NF) is achieved if the record is in 1NF and has no partial dependencies

• After a record is in 2NF and all transitive dependencies have been removed, then it is in third-normal form (3NF), which is generally sufficient for most databases

• A primary key is used to uniquely identify each record


Summary (continued)

• A common field is used to join data contained in different tables

• A foreign key is a common field that exists between two tables but is also a primary key in one of the tables

• A lookup table is a common term for a table referenced in a foreign key

• A Structured Query Language (SQL) is a data sublanguage that navigates the data stored within a database’s tables

Documents

Chapter 1 Overview of Database Concepts