The Database Development Process

© 2007 by Prentice Hall© 2007 by Prentice Hall 11

Chapter 2:Chapter 2: The Database The Database

Development Process Development Process

Modern Database Modern Database ManagementManagement

88thth Edition EditionJeffrey A. Hoffer, Mary B. Prescott, Jeffrey A. Hoffer, Mary B. Prescott,

Fred R. McFaddenFred R. McFadden

© 2007 by Prentice Hall© 2007 by Prentice HallChapter 2 22

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


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 Overall picture of organizational data at

high level of abstractionhigh level of abstraction Entity-relationship diagramEntity-relationship diagram Descriptions of entity typesDescriptions of entity types Relationships between entitiesRelationships between entities Business rulesBusiness rules


Figure 2-1 Segment from enterprise data model

Enterprise data model describes the high-level entities in an organization and the relationship between these entities


Information Systems Information Systems ArchitectureArchitecture

(ISA)(ISA) Conceptual blueprint for organization’s Conceptual blueprint for organization’s

desired information systems structuredesired information systems structure Consists of:Consists of:

Data (e.g. Enterprise Data ModelData (e.g. Enterprise Data Model––simplified ER simplified ER Diagram)Diagram)

ProcessesProcesses––data flow diagrams, process data flow diagrams, process decomposition, etc.decomposition, etc.

Data NetworkData Network––topology diagram (like Fig 1-9)topology diagram (like Fig 1-9) PeoplePeople––people management using project people management using project

management tools (Gantt charts, etc.)management tools (Gantt charts, etc.) Events and points in time (when processes are Events and points in time (when processes are

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

tables)tables)


Information EngineeringInformation Engineering A data-oriented methodology to create A data-oriented methodology to create

and maintain information systemsand maintain information systems Top-down planning–a generic IS Top-down planning–a generic IS

planning methodology for obtaining a planning methodology for obtaining a broad understanding of the IS needed broad understanding of the IS needed by the entire organizationby the entire organization

Four steps to Top-Down planning:Four steps to Top-Down planning: PlanningPlanning AnalysisAnalysis DesignDesign ImplementationImplementation


Information Systems Information Systems PlanningPlanning

(Table 2-1) (Table 2-1) PurposePurpose––align information align information

technology with organization’s technology with organization’s business strategiesbusiness strategies

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

2.2. Identify corporate planning objectsIdentify corporate planning objects

3.3. Develop enterprise modelDevelop enterprise model


Identify Strategic Planning Identify Strategic Planning Factors (Table 2-2)Factors (Table 2-2)

Organization goals–what we hope to Organization goals–what we hope to accomplishaccomplish

Critical success factors–what MUST Critical success factors–what MUST work in order for us to survivework in order for us to survive

Problem areas–weaknesses we now Problem areas–weaknesses we now havehave


Identify Corporate Planning Identify Corporate Planning Objects (Table 2-3)Objects (Table 2-3)

Organizational units–departmentsOrganizational units–departments Organizational locationsOrganizational locations Business functions–groups of business Business functions–groups of business

processesprocesses Entity types–the things we are trying Entity types–the things we are trying

to model for the databaseto model for the database Information systems–application Information systems–application

programsprograms


Develop Enterprise ModelDevelop Enterprise Model

Functional decompositionFunctional decomposition Iterative process breaking system Iterative process breaking system

description into finer and finer detaildescription into finer and finer detail Enterprise data model Enterprise data model

Planning matrixes Planning matrixes Describe interrelationships Describe interrelationships

between planning objectsbetween planning objects


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


Planning MatrixesPlanning Matrixes Describe relationships between Describe relationships between

planning objects in the organizationplanning objects 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


Example business function-Example business function-to-data entity matrix (Fig. 2-to-data entity matrix (Fig. 2-

3)3)


Two Approaches to Two Approaches to Database and IS Database and IS

DevelopmentDevelopment 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 initial prototypeDefine database during development of initial prototype Repeat implementation and maintenance activities with Repeat implementation and maintenance activities with

new prototype versionsnew prototype versions


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


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

(cont.)(cont.)Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purpose––preliminary understandingDeliverable––request for study

Database activity–– enterprise modeling and early conceptual data modeling


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

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Analysis

Purpose–thorough requirements analysis and structuringDeliverable–functional system specifications

Database activity–Thorough and integrated conceptual data modeling



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purpose–information requirements elicitation and structureDeliverable–detailed design specifications

Database activity– logical database design (transactions, forms, displays, views, data integrity and security)



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Physical Design

Purpose–develop technology and organizational specificationsDeliverable–program/data structures, technology purchases, organization redesigns

Database activity– physical database design (define database to DBMS, physical data organization, database processing programs)



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



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Maintenance

Purpose–monitor, repair, enhanceDeliverable–periodic audits

Database activity– database maintenance, performance analysis and tuning, error corrections


Prototyping Database Prototyping Database MethodologyMethodology(Figure 2.6) (Figure 2.6)


Prototyping Database Prototyping Database MethodologyMethodology

(Figure 2.6) (Figure 2.6) (cont.)(cont.)



(Figure 2.6)(Figure 2.6) (cont.) (cont.)



(Figure 2.6)(Figure 2.6) (cont.) (cont.)



(Figure 2.6) (Figure 2.6) (cont.)(cont.)


CASECASE Computer-Aided Software Engineering Computer-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 modeling–drawing entity-relationship Data modeling–drawing entity-relationship

diagramsdiagrams Code generation–SQL code for table creationCode generation–SQL code for table creation Repositories–knowledge base of enterprise Repositories–knowledge base of enterprise

informationinformation


Packaged Data ModelsPackaged Data Models

Model components that can be purchased, Model components that can be purchased, customized, and assembled into full-scale customized, and assembled into full-scale data modelsdata models

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


Managing ProjectsManaging Projects Project–a planned undertaking of related Project–a planned undertaking of related

activities to reach an objective that has a activities to reach an objective that has a beginning 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 commitment–review of systems Incremental commitment–review of systems development project after each development development project after each development phase with rejustification after each phasephase with rejustification after each phase


Managing Projects: People Managing Projects: People InvolvedInvolved

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


Database SchemaDatabase Schema Physical Schema Physical Schema

Physical structures–covered in Chapters 5 and 6Physical structures–covered in Chapters 5 and 6 Conceptual SchemaConceptual Schema

E-R models–covered in Chapters 3 and 4E-R models–covered in Chapters 3 and 4 External SchemaExternal Schema

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

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


Different people have different views of the database…these are the external schema

The internal schema is the underlying design and implementation

Figure 2-7 Three-schema architecture


Figure 2-8 Developing the three-tiered architecture


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


Pine Valley FurniturePine Valley Furniture

Segment of project data model (Figure 2-11)


Figure 2-12 Four relations (Pine Valley Furniture)


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

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The Database Development Process

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