Chapter 2 Database Development Process

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2009 Pearson Education, Inc. Publishing as Prentice Hall1

Chapter 2:The Database Development Process

Modern Database Management

9th Edition

Jeffrey A. Hoffer, Mary B. Prescott,Heikki Topi


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Enterprise Data Model

First step in database development

Specifies scope and general content

Overall picture of organizational data at high level of

abstraction

Entity-relationship diagram

Descriptions of entity types

Relationships between entities

Business rules


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Figure 2-1 Segment from enterprise data model

Enterprise data model

describes the high-

level entities in an

organization and therelationship between

these entities


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Information Systems Architecture

(ISA)

Conceptual blueprint for organizations desiredinformation systems structure

Consists of: Data (e.g. Enterprise Data Modelsimplified ER Diagram)

Processesdata flow diagrams, process decomposition, etc.

Data Networktopology diagram (like Fig 1-7)

Peoplepeople management using project managementtools (Gantt charts, etc.)

Events and points in time (when processes are performed)

Reasons for events and rules (e.g., decision tables)


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5

Information Engineering

A data-oriented methodology to create andmaintain information systems

Top-down planninga generic IS planningmethodology for obtaining a broad understandingof the IS needed by the entire organization

Four steps to Top-Down planning: Planning

Analysis

Design

Implementation


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Identify Strategic Planning Factors

(Table 2-2)

Organization goalswhat we hope to

accomplish

Critical success factorswhat MUST work in

order for us to survive

Problem areasweaknesses we now have


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Identify Corporate Planning Objects

(Table 2-3)

Organizational unitsdepartments

Organizational locations

Business functionsgroups of business

processes

Entity typesthe things we are trying to modelfor the database

Information systemsapplication programs


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Develop Enterprise Model

Functional decomposition

Iterative process breaking system description intofiner and finer detail

Enterprise data model

Planning matrixes

Describe interrelationshipsbetween planning objects


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Planning Matrixes

Describe relationships between planningobjects in the organization

Types of matrixes:

Location-to-function

Unit-to-function

IS-to-data entity

Supporting function-to-data entity IS-to-business objective


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Example Business Function-to-Data

Entity Matrix (Fig. 2-3)


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Two Approaches to Database and IS

Development SDLC

System Development Life Cycle Detailed, well-planned development process Time-consuming, but comprehensive Long development cycle

Prototyping Rapid application development (RAD) Cursory attempt at conceptual data modeling Define database during development of initial prototype Repeat implementation and maintenance activities with new

prototype versions


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Systems Development Life Cycle

(see also Figures 2.4, 2.5)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design


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(see also Figures 2.4, 2.5) (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purposepreliminary understanding

Deliverablerequest for study

Database activityenterprise modeling and

early conceptual data

modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Analysis

Purpose

thorough requirements analysis and

structuring

Deliverablefunctional system specifications

Database activity

thoroughand integrated conceptual

data modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purpose

information requirements elicitationand structure

Deliverabledetailed design specifications

Database activity

logical database design

(transactions, forms,

displays, views, data

integrity and security)


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Physical Design

Purpose

develop technology and

organizational specifications

Deliverableprogram/data

structures, technology purchases,

organization redesigns

Database activity

physical database design (define

database to DBMS, physical

data organization, database

processing programs)


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Implementation

Purpose

programming, testing, training,installation, documenting

Deliverableoperational programs,

documentation, training materials

Database activity

database implementation,

including coded programs,

documentation,

installation and conversion


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Maintenance

Purposemonitor, repair, enhance

Deliverableperiodic audits

Database activity

database maintenance,

performance analysis

and tuning, error

corrections


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CASE

Computer-Aided Software Engineering (CASE)software tools providing automated support for

systems development

Three database features: Data modelingdrawing entity-relationship diagrams

Code generationSQL code for table creation

Repositoriesknowledge base of enterpriseinformation


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Packaged Data Models

Model components that can be purchased,customized, and assembled into full-scale datamodels

Advantages

Reduced development time

Higher model quality and reliability

Two types:

Universal data models Industry-specific data models


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Managing Projects

Projecta planned undertaking of relatedactivities to reach an objective that has abeginning and an end

Involves use of review points for:

Validation of satisfactory progress Step back from detail to overall view Renew commitment of stakeholders

Incremental commitmentreview of systemsdevelopment project after each developmentphase with rejustification after each phase


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Database Schema

External Schema User Views

Subsets of Conceptual Schema

Can be determined from business-function/data entitymatrices

DBA determines schema for different users

Conceptual Schema E-R modelscovered in Chapters 3 and 4

Internal Schema

Logical structurescovered in Chapter 5 Physical structurescovered in Chapter 6


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Different people

have differentviews of the

databasethese

are the external

schema

The internal

schema is the

underlying

design andimplementation

Figure 2-7 Three-schema architecture


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Chapter 2 Database Development Process

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