fit328 02 the database development process

7/30/2019 FIT328 02 the Database Development Process

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LECTURE 2

THE DATABASEDEVELOPMENT PROCESS

[FIT328] Database Systems


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Credits

Modern Database Management, 8th edition

by: Jeffrey A. Hoffer, Mary B. Prescott,

Fred R. McFadden 2007 by Prentice Hall


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Objectives

Definition of terms Describe system development life cycle

Explain prototyping approach Explain roles of individuals Explain three-schema approach Explain role of packaged data models

Explain three-tiered architectures Explain scope of database design projects Draw simple data models


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Enterprise Data Model

First step in database development

Specifies scope and general content

Overall picture of organizational data at highlevel 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 1-9)

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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Information Engineering

A data-oriented methodology to create andmaintain information systems

Top-down planninga generic IS planning

methodology for obtaining a broad understandingof the IS needed by the entire organization Four steps to Top-Down planning:Planning

AnalysisDesignImplementation


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Information Systems Planning

Purposealign information technology withorganizations business strategies

Three steps:1. Identify strategic planning factors

2. Identify corporate planning objects

3. Develop enterprise model


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Identify Strategic Planning Factors

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

Organizational unitsdepartments

Organizational locations

Business functionsgroups of business processes Entity typesthe things we are trying to model for

the database

Information systemsapplication programs


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Develop Enterprise Model

Functional decomposition Iterative process breaking system description into finer and

finer detail

Enterprise data model

Planning matrixes Describe interrelationships

between planning objects


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Figure 2-2 Example of process decomposition of an order fulfillment

function (Pine Valley Furniture)


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Planning Matrixes

Describe relationships between planning objects inthe organization

Types of matrixes: Function-to-data entity

Location-to-function

Unit-to-function

IS-to-data entity

Supporting function-to-data entity

IS-to-business objective


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Figure 2-3 Example business function-to-data entity matrix


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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 initialprototype

Repeat implementation and maintenance activitieswith 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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Systems Development Life Cycle (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purposepreliminary understanding

Deliverablerequest for study

Database activity

enterprise modeling and

early conceptual data

modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Analysis

Purposethorough requirements analysis and

structuring

Deliverablefunctional system specifications

Database activityThorough

and integrated conceptual

data modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purposeinformation requirements elicitation

and 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

Purposedevelop 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

Purposeprogramming, 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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Figure 2-6 Prototyping Database Methodology


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Figure 2-6 Prototyping Database Methodology (cont.)


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CASE

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

Three database features:

Data modelingdrawing entity-relationship diagrams

Code generationSQL code for table creation

Repositoriesknowledge base of enterprise information


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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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Managing Projects: People Involved

Business analysts

Systems analysts

Database analysts and data modelers

Users

Programmers

Database architects

Data administrators

Project managers

Other technical experts


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Database Schema

Physical Schema Physical structurescovered in Chapters 5 and 6

Conceptual Schema E-R modelscovered in Chapters 3 and 4

External Schema User Views Subsets of Conceptual Schema

Can be determined from business-function/dataentity matrices

DBA determines schema for different users


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Figure 2-7 Three-schema architecture

Different people

have differentviews of the

databasethese

are the external

schema

The internal

schema is the

underlying

design andimplementation


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Figure 2-8 Developing the three-tiered architecture


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Figure 2-9 Three-tiered client/server database architecture


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Figure 2-11 Segment of project data model (Pine Valley Furniture)


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Figure 2-12 Four relations (Pine Valley Furniture)


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Figure 2-12 Four relations (Pine Valley Furniture) (cont.)

fit328 02 the database development process

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