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2007 by Prentice Hall 2007 by Prentice Hall 11

Chapter 2:Chapter 2:The Database DevelopmentThe Database Development

ProcessProcess

M o d e r n D a t a b as e M a n a g e m e n to d e rn D a t a b a s e M a n a g e m e n t8 thh Ed i t i onEd i t i on

Je f f rey A . H o f fe r, M a ry B . P re s co t t ,e f f rey A . Ho f fe r, M a ry B . P re s co t t ,F r e d R . M cFaddenred R . McFadden


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22 2007 by Prentice Hall 2007 by Prentice HallChapter 2

ObjectivesObjectives Definition of termsDefinition of terms Describe system development life cycleDescribe system development life cycle Explain prototyping approachExplain prototyping approach

Explain roles of individualsExplain roles of individuals Explain three-schema approachExplain three-schema approach Explain role of packaged data modelsExplain role of packaged data models Explain three-tiered architecturesExplain three-tiered architectures

Explain scope of database design projectsExplain scope of database design projects Draw simple data modelsDraw simple data models


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Enterprise Data ModelEnterprise Data Model

First step in database developmentFirst step in database development

Specifies scope and general contentSpecifies scope and general content

Overall picture of organizational data at highOverall picture of organizational data at highlevel of abstractionlevel of abstraction

Entity-relationship diagramEntity-relationship diagram

Descriptions of entity typesDescriptions of entity types Relationships between entitiesRelationships between entities

Business rulesBusiness 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 ArchitectureInformation Systems Architecture

(ISA)(ISA)

Conceptual blueprint for organizations desiredConceptual blueprint for organizations desiredinformation systems structureinformation systems structure

Consists of:Consists of:

Data (e.g. Enterprise Data ModelData (e.g. Enterprise Data Model

simplified ERsimplified ER

Diagram)Diagram) ProcessesProcessesdata flow diagrams, process decomposition,data flow diagrams, process decomposition,

etc.etc. Data NetworkData Networktopology diagram (like Fig 1-9)topology diagram (like Fig 1-9)

PeoplePeoplepeople management using project managementpeople management using project managementtools (Gantt charts, etc.)tools (Gantt charts, etc.) Events and points in time (when processes areEvents and points in time (when processes are

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


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Information EngineeringInformation Engineering

A data-oriented methodology to create andA data-oriented methodology to create andmaintain information systemsmaintain information systems Top-down planninga generic IS planningTop-down planninga generic IS planning

methodology for obtaining a broadmethodology for obtaining a broad

understanding of the IS needed by the entireunderstanding of the IS needed by the entireorganizationorganization

Four steps to Top-Down planning:Four steps to Top-Down planning: P l ann i ngl ann ing Ana l ys i sna l y s i s Des i gnes ign Imp l emen ta t i onmp l emen ta t i on


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Information Systems PlanningInformation Systems Planning

(Table 2-1)(Table 2-1)

PurposePurposealign information technologyalign information technology

with organizations business strategieswith organizations business strategies

Three steps:Three steps:1.1. Identify strategic planning factorsIdentify strategic planning factors

2.2. Identify corporate planning objectsIdentify corporate planning objects

3.3. Develop enterprise modelDevelop enterprise model


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Identify Strategic PlanningIdentify Strategic Planning

Factors (Table 2-2)Factors (Table 2-2)

Organization goalswhat we hope toOrganization goalswhat we hope to

accomplishaccomplish Critical success factorswhat MUST workCritical success factorswhat MUST work

in order for us to survivein order for us to survive

Problem areasweaknesses we now haveProblem areasweaknesses we now have


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Identify Corporate PlanningIdentify Corporate Planning

Objects (Table 2-3)Objects (Table 2-3) Organizational unitsdepartmentsOrganizational unitsdepartments

Organizational locationsOrganizational locations Business functionsgroups of businessBusiness functionsgroups of business

processesprocesses

Entity typesthe things we are trying toEntity typesthe things we are trying tomodel for the databasemodel for the database

Information systemsapplication programsInformation systemsapplication programs


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Develop Enterprise ModelDevelop Enterprise Model

Functional decompositionFunctional decomposition Iterative process breaking system descriptionIterative process breaking system description

into finer and finer detailinto finer and finer detail Enterprise data modelEnterprise data model

Planning matrixesPlanning matrixes Describe interrelationshipsDescribe interrelationships

between planning objectsbetween planning objects


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Figure 2-2 Example of process decomposition of an

order fulfillment function (Pine Valley Furniture)

Decomposition = breaking

large tasks into smaller tasks

in a hierarchical structure chart


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Planning MatrixesPlanning Matrixes Describe relationships between planningDescribe relationships between planning

objects in the organizationobjects in the organization Types of matrixes:Types of matrixes:

Function-to-data entityFunction-to-data entity Location-to-functionLocation-to-function Unit-to-functionUnit-to-function

IS-to-data entityIS-to-data entity Supporting function-to-data entitySupporting function-to-data entity IS-to-business objectiveIS-to-business objective

l b f


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Example business function-to-Example business function-to-

data entity matrix (Fig. 2-3)data entity matrix (Fig. 2-3)


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Two Approaches to DatabaseTwo Approaches to Database

and IS Developmentand IS Development SDLCSDLC

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

PrototypingPrototyping Rapid application development (RAD)Rapid application development (RAD) Cursory attempt at conceptual data modelingCursory attempt at conceptual data modeling Define database during development of initialDefine database during development of initial

prototypeprototype Repeat implementation and maintenance activitiesRepeat implementation and maintenance activities

with new prototype versionswith new prototype versions


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Systems Development Life CycleSystems Development Life Cycle

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

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purposepreliminary understandingDeliverablerequest for study

Database activityenterprise 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 activityThoroughand integrated conceptual

data modeling


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Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purposeinformation requirements elicitationand structure

Deliverabledetailed design specifications

Database activitylogical 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 activityphysical 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

P t t i D t b M th d l


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Prototyping Database Methodology(Figure 2.6)

Prototyping Database Methodology


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(Figure 2.6) (cont.)



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CASECASE Computer-Aided Software EngineeringComputer-Aided Software Engineering

(CASE)software tools providing automated(CASE)software tools providing automated

support for systems developmentsupport for systems development

Three database features:Three database features: Data modelingdrawing entity-relationshipData modelingdrawing entity-relationship

diagramsdiagrams

Code generationSQL code for table creationCode generationSQL code for table creation Repositoriesknowledge base of enterpriseRepositoriesknowledge base of enterprise

informationinformation


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Packaged Data ModelsPackaged Data Models

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

AdvantagesAdvantages Reduced development timeReduced development time Higher model quality and reliabilityHigher model quality and reliability

Two types:Two types: Universal data modelsUniversal data models Industry-specific data modelsIndustry-specific data models


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Managing ProjectsManaging Projects Projecta planned undertaking of relatedProjecta planned undertaking of related

activities to reach an objective that has aactivities to reach an objective that has abeginning and an endbeginning and an end

Involves use of review points for:Involves use of review points for:Validation of satisfactory progressValidation of satisfactory progress Step back from detail to overall viewStep back from detail to overall view Renew commitment of stakeholdersRenew commitment of stakeholders

Incremental commitmentreview ofIncremental commitmentreview ofsystems development project after eachsystems development project after eachdevelopment phase with rejustificationdevelopment phase with rejustificationafter each phaseafter each phase


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Managing Projects: People InvolvedManaging Projects: People Involved

Business analystsBusiness analysts Systems analystsSystems analysts

Database analysts and data modelersDatabase analysts and data modelers

UsersUsers ProgrammersProgrammers

Database architectsDatabase architects

Data administratorsData administrators

Project managersProject managers

Other technical expertsOther technical experts


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Database SchemaDatabase Schema

Physical SchemaPhysical Schema Physical structurescovered in Chapters 5 and 6Physical structurescovered in Chapters 5 and 6

Conceptual SchemaConceptual Schema E-R modelscovered in Chapters 3 and 4E-R modelscovered in Chapters 3 and 4

External SchemaExternal Schema User ViewsUser Views Subsets of Conceptual SchemaSubsets of Conceptual Schema Can be determined from business-function/dataCan be determined from business-function/data

entity matricesentity matrices DBA determines schema for different usersDBA determines schema for different users


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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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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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Pine Valley FurniturePine Valley Furniture

Segment of project data model (Figure 2-11)


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Figure 2-12 Four relations (Pine Valley Furniture)


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3737 2007 by Prentice Hall 2007 by Prentice HallCh t 2

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

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