Chapter+2+ +the+Database+Development+Process

8/13/2019 Chapter+2+ +the+Database+Development+Process

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2007 by Prentice Hall 1

Chapter 2:The Database DevelopmentProcess

Modern Database Management8 th Edition

Jeffrey A. Hoffer, Mary B. Prescott,Fred R. McFadden


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2007 by Prentice HallChapter 2 2

ObjectivesDefinition of termsDescribe system development life cycleExplain prototyping approach

Explain roles of individualsExplain three-schema approachExplain role of packaged data modelsExplain three-tiered architectures

Explain scope of database design projectsDraw simple data models


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Enterprise Data Model

First step in database developmentSpecifies scope and general content

Overall picture of organizational data at highlevel of abstractionEntity-relationship diagram

Descriptions of entity typesRelationships between entitiesBusiness rules


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Figure 2-1 Segment from enterprise data model

Enterprise data modeldescribes the high-level entities in an

organization and therelationship betweenthese entities


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Information Systems Architecture(ISA)

Conceptual blueprint for organizations desiredinformation systems structureConsists of:

Data (e.g. Enterprise Data Model simplified ERDiagram)Processes data flow diagrams, processdecomposition, etc.Data Network topology diagram

People people management using projectmanagement tools (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 systemsTop-down planning a generic IS planningmethodology for obtaining a broadunderstanding of the IS needed by the entireorganizationFour steps to Top-Down planning:

Planning AnalysisDesignImplementation


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Information Systems Planning

Purpose align information technologywith organizations business strategies

Three steps:1. Identify strategic planning factors2. Identify corporate planning objects

3. Develop enterprise model


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Identify Strategic Planning

FactorsOrganization goals what we hope toaccomplishCritical success factors what MUST workin order for us to surviveProblem areas weaknesses we now have


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Identify Corporate PlanningObjects

Organizational units departments

Organizational locationsBusiness functions groups of businessprocesses

Entity types the things we are trying tomodel for the databaseInformation systems application programs


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Develop Enterprise Model

Functional decompositionIterative process breaking system description

into finer and finer detail

Enterprise data model

Planning matrixesDescribe inter relationshipsbetween planning objects


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Example of process decomposition of an orderfulfillment function (Pine Valley Furniture)

Decomposition = breakinglarge tasks into smaller tasksin a hierarchical structurechart


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Planning MatrixesDescribe relationships between planningobjects in the organizationTypes of matrixes:

Function-to-data entityLocation-to-functionUnit-to-function

IS-to-data entitySupporting function-to-data entityIS-to-business objective


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Example business function-to-data entity matrix


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Two Approaches to Databaseand IS Development

SDLCSystem Development Life CycleDetailed, well-planned development processTime-consuming, but comprehensiveLong development cycle

PrototypingRapid application development (RAD)Cursory attempt at conceptual data modelingDefine database during development of initialprototypeRepeat implementation and maintenance activitieswith new prototype versions


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Systems Development Life Cycle

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purpose preliminary understandingDeliverable request for study

Database activity enterprise modeling andearly conceptual datamodeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Analysis

Purpose thorough requirements analysis andstructuringDeliverable functional system specifications

Database activity Thoroughand integrated conceptualdata modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purpose information requirements elicitationand structureDeliverable detailed design specifications

Database activity logical database design(transactions, forms,displays, views, dataintegrity and security)


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Physical Design

Purpose develop technology andorganizational specificationsDeliverable program/datastructures, technology purchases,organization redesigns

Database activity physical database design (definedatabase to DBMS, physicaldata organization, databaseprocessing programs)


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Systems Development Life Cycle(see also Figures 2.4, 2.5) (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Implementation

Purpose programming, testing, training,installation, documentingDeliverable operational programs,documentation, training materials

Database activity database implementation,including coded programs,documentation,installation and conversion


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Systems Development Life Cycle(see also Figures 2.4, 2.5) (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Maintenance

Purpose monitor, repair, enhanceDeliverable periodic audits

Database activity database maintenance,performance analysisand tuning, errorcorrections


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Prototyping Database Methodology


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CASEComputer-Aided Software Engineering(CASE) software tools providing automatedsupport for systems development

Three database features:Data modeling drawing entity-relationshipdiagrams

Code generation SQL code for table creationRepositories knowledge base of enterpriseinformation


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Packaged Data Models

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

AdvantagesReduced development timeHigher model quality and reliability

Two types:Universal data modelsIndustry-specific data models


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Managing ProjectsProject a planned undertaking of relatedactivities to reach an objective that has abeginning and an end

Involves use of review points for: Validation of satisfactory progressStep back from detail to overall viewRenew commitment of stakeholders

Incremental commitment review ofsystems development project after eachdevelopment phase with rejustificationafter each phase


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Managing Projects: People Involved

Business analystsSystems analystsDatabase analysts and data modelers

UsersProgrammersDatabase architectsData administratorsProject managersOther technical experts


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Database Schema

Physical SchemaPhysical structures covered in Chapters 5 and 6

Conceptual SchemaE-R models covered in Chapters 3 and 4

External SchemaUser ViewsSubsets of Conceptual SchemaCan be determined from business-function/dataentity matricesDBA determines schema for different users


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Different people

have differentviews of thedatabasethese

are the externalschema

The internalschema is theunderlyingdesign andimplementation

Three-schema architecture


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Developing the three-tiered architecture


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Three-tiered client/server database architecture


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Pine Valley Furniture

Segment of project data model (Figure 2-11)


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Four relations (Pine Valley Furniture)


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2007 b P ti H llCh 2 37

Four relations (Pine Valley Furniture) (cont.)

Chapter+2+ +the+Database+Development+Process

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