This document provides an overview of database requirements, design, and development. It discusses the steps in the systems development life cycle as they relate to database projects, including project identification and selection, requirements analysis, logical design, physical design, implementation, and maintenance. Examples of conceptual data modeling and entity relationship diagrams are also presented to illustrate how requirements can be modeled visually.

1. 1
Database Requirements
and Design

2. 2
DATA
PEOPLE
PROCEDURES
HARDWARE
SOFTWARE
The Product: a working system

3. 3
Database development activities during the
systems development life cycle (SDLC)
Project Identification
and Selection
Project Initiation
and Planning
Analysis
Physical Design
Implementation
Maintenance
Logical Design

4. 4
Project Identification & Selection
Purpose: to develop a preliminary
understanding of the business situation that
has caused the request for a new or
enhanced information system.
Deliverable: a formal request for services

5. 5
Project Identification and
Selection
 Printing Company: use internet to request
quotes, place orders and check order status
 Video Game Store: track customer information,
track customer purchases, maintain inventory
 Elementary school After School program:
student records, important information, account
balances
 Interpreter’s Organizer: assignment status,
income, costs, taxes

6. 6
Project Identification and
Selection
 Groups of 3-5, talk to me if you are thinking about an
individual assignment
 I would advise you use either a devise a case study with
your group where you implement a database, or use a
company/scenario that someone in your group is familiar
with. Make sure everyone in the group understands the
scenario
 The next step in your group process should be to sit down
and talk about the System Requirement. Make sure
everyone in your group understands what data you want
to get from the database.

7. 7
Project Initiation and
Planning
System Requirements:
 Information requirements of the
system
 Stakeholders
 Constraints
 Application environment

8. 8
Case Study
The Clearwater Traders
Sales Order Database

9. 9
Overview
Markets a line of clothing and sporting goods via
mail-order catalogs
To remain competitive, company managers want to
create a database to allow Internet customers to:
• Browse the catalog on-line
• Place orders
• Check order status status

10. 10
Information Requirements
System must do all of the following:
• Track information about customers and customer orders
• Track customer orders
• Track inventory information so customers can find out if
an item is available
• Have intranet applications, so Clearwater Traders
personnel can:
• Add, update, and delete inventory items
• Update inventory amounts when new shipments are received
• Modify item prices

11. 11
Stakeholders
Company management
Clearwater Traders personnel
Customers

12. 12
Constraints
System must be operational by April 2001
System must not require additional purchase
of software/hardware
Other possible constraints? Training employees, …

13. 13
Application Environment
Access 2000 on networked PCs
Expansion to Web sites using Visual Basic
and Personal Web Server

14. 14
Logical Design
Purpose: to elicit and structure all
information requirements
Deliverables: detailed functional specs for
data, forms, reports, displays, and rules
(logic, algorithms)

15. 15
Principles of Conceptual
Database Design
 Identify basic data needs and create
conceptual data models that record
needed data elements and their
relationships
 Your local Bank:
 How many checking accounts do we have?
 How many savings accounts?
 How many customers?
 How do we get each customer the right
monthly statement?
 How do I get a weekly report of overdue loan
payments?

16. 16
Reality and Requirements
Definition
 Requires identifying user information
requirements and representing them in a
well-defined model
 Model – a representation of reality that retains
only selected details
 Database Management System (DBMS)
manages the database so that each user
can record, access, and manipulate the
data that is the “model of reality” of
interest to the user
 Requires mapping – associating elements in
one sphere with elements in another sphere

17. 17
Conceptual Data Models
 Object-oriented model
 Represents real-world entities as objects
rather than as records
• Have their own object identities and attributes
• Participate in relationships
 Describes ways of manipulating data that
focuses on the data and the manipulation
(query, computation, update, etc.)

18. 18
Fundamentals
 Objects
 Important to users in the portion of
reality modeled
• Concrete objects
• People, automobiles, trees, dishwashers, houses,
hammers, books, etc.
• Conceptual objects
• Companies, skills, organizations, product
designs, business transactions, job
classifications, etc.

19. 19
Entity Relationship Diagram
An entity-relationship diagram is a
data modeling technique that creates a
graphical representation of the entities,
and the relationships between entities,
within an information system.

20. 20
The three main components
of an ERD are:
 The entity is a person, object, place or
event for which data is collected
 The relationship is the interaction
between the entities
 The cardinality defines the relationship
between the entities in terms of numbers.

21. 21
The steps involved in
creating an ERD are:
 Identify the entities;
 Determine all significant interactions;
 Analyze the nature of the interactions;
 Draw the ERD

22. 22
Synonyms you should know…
Entity = class = relation = table
Attribute = column
Instance = row
rows
columns
table

23. 23
Relationships
 MARRIED-MAN IS-MARRIED-TO
MARRIED-WOMAN
 MARRIED-MAN = {Adam, David, John} and
 MARRIED-WOMAN = {Joan, Linda, Michelle}
and
 Adam is-married-to Joan
 David is-married-to Linda
 John is-married-to Michelle
 IS-MARRIED-TO =
 { (Adam, Joan), (David, Linda), (John,
Michelle) }

24. 24
Representations of a
Relationship
Married
Man
Married
Woman
IS
MARRIED
TO
(a) The IS MARRIED TO relationship
Adam ----------------------------------- Joan
David ----------------------------------- Linda
John ----------------------------------- Michelle
(b) Some instances of IS MARRIED TO

25. 25
Cardinality
 Refers to the maximum number of
instances of 1 object set related to a
single instance of the other object
set
Married
Man
Married
Woman
IS
MARRIED
TO
1 1
Supervisor WorkerSupervises1 *
1:1 relationship
1:M or 1:* relationship

26. 26
Basic E-R Notation

27. 27
Sample E-R Diagram

28. 28
E-R model with only the necessary entities

29. 29
Primary key attribute

30. 30
Composite key attribute

31. 31
Relationship types and instances
(a) Relationship type “Completes”

32. 32
Cardinality constraints
(a) Relationship showing maximum cardinality only.

33. 33
(b) Relationship showing max & min cardinality
Cardinality constraints

34. 34
Building a Conceptual Data
Model from a Purchase Order
PAYMENT
Check #
Date
ORDER
Number
Tax
TotalDate
VENDOR
Number
Name
Address
* INCLUDES *
1
MADE FROM
*
1
PAID WITH
1
PRODUCT
Stock #
Description
Price

35. 35
Representing Tables
(entities)
 Vendor (Number, Name, Address)
 Product (Stock #, Description, Price)
 Order (Number, Date, Tax, Total)
 Payment (Check #, Date)
Attributes are in parentheses
Primary key is underlined.

36. 36
Physical Design
Purpose: to develop all technology &
organizational specs
Deliverables: program & database
structures, technology purchases, physical
site plans and organizational redesigns

37. 37
Implementation
Purpose: to write programs, build data
files, test and install the new system, train
users, and finalize documentation
Deliverables: programs that work
accurately and to specs, documentation
(user and system), and training materials.

38. 38
For Practice...
Identify a potential key value for each of the
following entities:
• Customer (Cust-Name, Cust-ID, Address, Country,
Balance, Month-to-date-payments)
• Sales Rep (Comm%, Office, Manager-ID,
Sales Rep Name, Sales Rep ID)
• Product (Prod-Desc, Mfg-ID, Cost, Price, Prod-ID)

39. 39
For Practice...
For each of the following, draw a data model
showing a relationship between objects and
attributes of the objects. Indicate cardinality.
• Students take classes and get grades in the classes.
• Sections of courses are offered at specified times and in specified
rooms of buildings.
• Employees work a certain number of hours and have a certain
supervisor.
• People subscribe to magazines, and their subscriptions have
beginning and ending dates.