1. Overview of Database Development
Data Modeling and Relational Database Design

2. Objectives Describe the phases of the database development process
Describe the phases of the application development process
Explain conceptual data modeling and database design

3. SYSTEM DEVELOPMENT LIFE CYCLE
Strategy
and
Analysis
Design
Build
and
Document
Transition
Production

4. Database Development Process
Business Requirements
Information
Process
Conceptual
Data Modeling
Database Design
Database Build
Cross-checking
Function Modeling
Application Design
Application Build
ER model,
entity definition
Function hierarchy,
function definition
Module (screen, report, menu, program design)
Table, index,
view
Cross-checking
Database
Application
Operational System

5. Database Development Process
Business Information Requirements
Conceptual Data Modeling
Business view
Logical Database Design
Systems view
Physical Database Build
Operational Database

6. Terminology CONCEPTUAL LOGICAL (Business view) (Systems view) ANALYSIS
DESIGN
ENTITY
TABLE
RELATIONSHIP
FOREIGN KEY
ATTRIBUTE
COLUMN
PRIMARY KEY
UNIQUE
IDENTIFIER
UNIQUE KEY

7. Information Models Organize thought processes
Accurately model business data
Communicate with stakeholders
Analyze the scope
Provide sound basis for system design

8. Goals of Conceptual Data Modeling
Robust syntax
User communication
Ease of development
Definition of scope
Integration of multiple applications

9. Modeling Basic Entities and Attributes

10. Overview Why conceptual modeling?
Introduction of the Key role players:
Entities
Attributes
Relationships

11. Why Create a Conceptual Model?
It describes exactly the information needs of the business
It facilitates discussion
It helps to prevent mistakes, misunderstanding
It forms important “ideal system” documentation
It forms a sound basis for physical database design
It is a very good practice with many practitioners

12. Conceptual Model Between Dream and Reality...

13. Entity Relationship Modeling
Models business, not implementation
Is a well-established technique
Has a robust syntax
Results in easy-to-read diagrams…
...although they may look rather complex at first sight

14. Goals of Entity Relationship Modeling
Capture all required information
Information appears only once
Model no information that is derivable from other information already modeled
Information is in a predictable, logical place

15. CONCEPTUAL DATA MODELS
Model of system in client’s mind
Entity model of client’s model
Table model of entity model
Server
Tables on disk

16. Database Types
ER Model
Hierarchical
Network
Relational

17. ENTITY RELATIONSHIP MODEL
Create an entity relationship diagram from business specifications or narratives
EMPLOYEE
#* number
* name
o job title
DEPARTMENT
#* number
* name
o location
assigned to
composed of
Scenario
“. . . Assign one or more employees to a department . . .”
“. . . Some departments do not yet have assigned employees . . .”

18. Entity An Entity is: Examples: objects, events
“Something” of significance to the business about which data must be known.
A name for the things that you can list.
Usually a noun.
Examples: objects, events
Entities have instances.

19. Identify and Model Entities
Identify a noun
Is it significant?
Is there information about it that the business needs to keep?
Is it a group or an instance?
Name the entity
Write a description of it
Identify a few attributes
Draw a soft box for it

20. Entity Instances EMPLOYEE DEPARTMENT Head office Personnel Finance
Sales
EMPLOYEE
DEPARTMENT

21. Identifying a Unique Instance
EMPLOYEE
badge number
name
date of birth
salary

22. Entities and Instances
PERSON
PRODUCT
PRODUCT TYPE
EMPLOYMENT CONTRACT
JOB
SKILL LEVEL
TICKET RESERVATION
PURCHASE
ELECTION
PRINTER PREFERENCE
DOCUMENT VERSION
Mahatma Gandhi
2.5 x 3.5 mm copper nail
Nail
My previous contract
Violinist
Fluent
Tonight: Hamlet in the Royal
The CD I bought yesterday
For parliament next fall …

23. Entities and Sets
An entity represents a set of instances that are of interest to a particular business.
JOB
manager
cook
waitress
dish washer
financial controller
porter
waiter
piano player

24. Attribute Also represents something of significance to the business
Is a single valued property detail of an entity
Is a specific piece of information that:
Describes
Quantifies
Qualifies
Classifies
Specifies
an entity.

25. Attribute Examples Entity Attribute EMPLOYEE
CAR
ORDER
JOB
TRANSACTION
EMPLOYMENT CONTRACT
Attribute
Family Name, Age, Shoe Size, City, , …
Model, Weight, Catalog Price, …
Order Date, Ship Date, …
Title, Description, ...
Amount, Transaction Date, …
Start Date, Salary, ...

26. Entity Representation in Diagram
Drawn as a “softbox”
Name singular
Name inside
Neither size, nor position has a special meaning
EMPLOYEE
TICKET
RESERVATION
JOB ASSIGNMENT
JOB
ORDER
ELECTION
During design, entities usually lead to tables.

27. Attributes in Diagrams
EMPLOYEE * family Name address birth Date o shoe Size o
JOB title o description * o * *
Mandatory attribute, that is, known and available for every instance
Optional attribute, that is, unknown or unimportant to know for some instances o
During design, attributes lead to columns.

28. ENTITY RELATIONSHIP MODELING CONVENTIONS
Soft box
Singular, unique name
Uppercase
Synonym in parentheses
Attribute
Singular name
Lowercase
Mandatory marked with “*”
Optional marked with “o”
EMPLOYEE
#* number
* name
o job title
DEPARTMENT
#* number
* name
o location
assigned to
composed of
Unique Identifier (UID)
Primary marked with “#”
Secondary marked with “(#)”