chap02: the database development process
TRANSCRIPT
© 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
ManagementManagement88thth Edition Edition
Jeffrey A. Hoffer, Mary B. Prescott, Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFaddenFred R. McFadden
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 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
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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
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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)
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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 by broad understanding of the IS needed by the entire organizationthe entire organization
Four steps to Top-Down planning:Four steps to Top-Down planning: PlanningPlanning AnalysisAnalysis DesignDesign ImplementationImplementation
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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 objects3.3. Develop enterprise modelDevelop enterprise model
88© 2007 by Prentice Hall© 2007 by Prentice HallChapter 2
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
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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 to Entity types–the things we are trying to
model for the databasemodel for the database Information systems–application Information systems–application
programsprograms
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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
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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 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
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Example business function-Example business function-to-data entity matrix (Fig. 2-to-data entity matrix (Fig. 2-
3)3)
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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
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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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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
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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
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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 DesignLogical Design
Purpose–information requirements elicitation and structureDeliverable–detailed design specifications
Database activity– logical database design (transactions, forms, displays, views, data integrity and security)
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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
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)
2020© 2007 by Prentice Hall© 2007 by Prentice HallChapter 2
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
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 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
Maintenance
Purpose–monitor, repair, enhanceDeliverable–periodic audits
Database activity– database maintenance, performance analysis and tuning, error corrections
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Prototyping Database Prototyping Database MethodologyMethodology(Figure 2.6) (Figure 2.6)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 2.6) (Figure 2.6) (cont.)(cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 2.6)(Figure 2.6) (cont.) (cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 2.6)(Figure 2.6) (cont.) (cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 2.6) (Figure 2.6) (cont.)(cont.)
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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
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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 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
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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
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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
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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
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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
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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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Figure 2-12 Four relations (Pine Valley Furniture) (cont.)