PPT Slides by Dr. Craig Tyran & Kraig Pencil Database Design MIS 320 Kraig Pencil Summer 2014 1

PPT Slides by Dr. Craig Tyran & Kraig Pencil

Database Design

MIS 320

Kraig Pencil

Summer 2014

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Game Plan

• Introduction

• Data base design– Database scenario

– Key questions/answers

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A. Introduction

Remember … ?

CNN: Internet is “Top innovation” of past 25 years (1/18/05)

But Kraig Pencil says …

The relational database is equally important

Really? Why?

The Internet would not be nearly as successful without relational databases providing rich information.

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A. IntroductionYou can ask a database questions

– How many cans of chicken soup do we have in inventory?

– How large is the average pay raise in each department?

– Who are my best/worst customers?

– What else have I-Pod buyers also purchased?

– Is this airline passenger a known terrorist?

– Who has friended Gayle Zhang?

– Who else might Gayle want to consider friending?

With the right data and a well-designed database, you can ask anything.

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A. Introduction

Who works with databases?• Database programmers• Database analysts• Database designers• Database administrators• Data administrators• Website designers/programmers• Many non-IT users!

– Marketers– Financial analysts– Human resources managers …. And more

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A. Introduction1. What does an organization do with

data/information?• Capture, cradle, and process transaction

data/information• e.g., TPS

• Use information to make decisions• e.g., DSS

• “Oversee” the information• e.g., Who can view or use what info?, How to

back up info?, How long to retain info?

2. What can help support the above?• A database management system 6


B. Business Scenario

1. Is data management a problem?For generations we stored information in filing cabinets, then in Excel spreadsheets. But as the amount of data has grown those methods have become …–Inefficient – and expensive – to store and gather data–Unable to support for decision making basedon data

A database management system is needed to support business !!!


B. Business Scenario

1. Northwind Incorporated– Distributor of food and beverage products– Customers: Restaurants and specialty food stores– Suppliers: Come from around the world

– In the lab and lectures, you will seehow efficiently a database management systemcan provide rich information to theorganization.


C. Steps of Database Design 1. What kinds of “things” does an organization

want to collect information about? Determine the Entities

• For Northwind Inc, the “entities” of interest include:

– Customers– Suppliers– Employees– Products– Etc.


C. Steps of Database Design (cont.)2. What specific information about each

entity is important? Determine the attributes for each entity

• Example: For the Employee entity, attributes may include• Employee name

• Address

• Hourly rate

• Etc.

• Who is this guy doing the interview?• A “business analyst”

For each employee, we keep track of …

President of Northwind

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C. Steps of Database Design (cont.)

3. How do we organize the data? Which type of database “model” shall we use?

– Assume: Use the most popular model Relational model

• “Relation” refers to ???

• Data is organized as a linked set of tables

• An example of a relational database management system that you are using in MIS 320 : ___________

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Northwind Database in MS Access

Sample Entity-Relationship Diagram (aka an “ERD” or “ER diagram”)


B. Database Questions (cont.)4. What are the important aspects of a data table?

– Terminology for data tables

• Field (i.e. column)

– Attribute of the entity

• Record (i.e. row)

– An instance of an entity

• File (i.e., table)

– Collection of records for an entity

• Primary key

– Unique identifier for each record

– Often a unique “ID code” is created

– Example: See next figure

Find all records in the Customer file for which the customer’s name field is Serena Lewis

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Database Tables

Supplier ID Company Name Street Address City State

1001 ACME Inc. 123 Easy St. Deming WA

1002 XYZ Corporation 456 Maple St. Bellingham WA

1003 ProductCo Inc. 389 Main St. Seattle WA

… … … … …

Product ID Product Name Unit Price ($) Supplier ID

800 Cheddar Cheese 15 1001

801 Swiss Cheese 12 1001

802 Chuckanut Red Wine

20 1002

… …. …. …

Supplier Table

Product Table

What are examples of a) Field, b) Record, c) File,

and d) appropriate Primary Key ??


C. Steps of Database Design (cont.)5. What are the relationships between the entities?

– A database involves tables that are linked together – When building a database, we need to know how to link the tables

• i.e., We need to know how the entities are related!

• e.g., A Supplier provides a Product.– If we know who the supplier is, we

can find all the products they have supplied to us.

– For any product, we should be ableto find the supplier’s address.

– Develop a “blueprint” diagram for database design

Entity-relationship diagram

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B. Database Questions (cont.)5. What are the relationships between the entities? (cont.)

– Possible “relationship types”• A) one to one, B) one to many, c) many to many

– “one” means “at most one” – “many” means “more than one”

– Example: • Entities: Supplier, Product• What is the relationship type? We are told that:

– A supplier can provide many different kinds of products. – A product can be supplied by a max of one supplier.

• Entity-Relationship Diagram:

Supplier Product?????? manyone

Provides16


B. Database Questions (cont.)5. Relationship symbols: these all mean the same thing

The textbook used “crowsfoot” symbols

Access uses “1 – ∞” symbols

Access uses “ – ∞” symbols

Ignore these “inner” symbols

One Many


B. Database Questions (cont.)5. (cont.)

– Foreign key• Serves as a “link” between data files/tables

• A field in one file/table that serves as a primary key in another file/table

• How to determine the foreign key?– For a “one to many” relationship, the primary key on the

“one” side of the relationship is added to the table on the “many” side

• See examples

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Database Tables: Northwest Inc.Supplier ID Company Name Street Address City State

1001 ACME Inc. 123 Easy St. Deming WA

1002 XYZ Corporation 456 Maple St. Bellingham WA

1003 ProductCo Inc. 389 Main St. Seattle WA

… … … … …

Product ID Product Name Unit Price ($) Supplier ID Category ID

800 Cheddar Cheese 15 1001 10

801 Swiss Cheese 12 1001 10

802 Chuckanut Red Wine

20 1002 20

… …. …. … …

Category ID Category Name Description

10 Dairy Cheese and milk products

20 Spirits Wine and liquors

… … …

Supplier Table

Product Table

Category Table


Northwind Database in MS Access: Primary/Foreign KeysWhere are the primary keys? The foreign keys?


C. Steps of Database Design (cont.)6. What do we do with the entity-

relationship diagram? (cont.)– ERD can be reviewed with client (Is the

design correct for the client’s needs?)– Database design can be used to build the

database• e.g., Build database in MS Access

– Can database design get more complicated than this?

• Yes! • But … the previous example will suffice

for MIS 320– The lab database projects will

typically focus on “one to many” types of relationships

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Terminology Summary

Easy to understand

Academic

Table (File) Entity / Relation

Column Field Attribute

Row Record Instance

The terms in each row have very similar meanings.

For this course, learn all of the terms, but do not be concerned about the nuanced differences between terms in the same row.

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Documents

PPT Slides by Dr. Craig Tyran & Kraig Pencil Database Design MIS 320 Kraig Pencil Summer 2014 1