Chap02: The database Development process

© 2007 by Prentice Hall© 2007 by Prentice Hall 11
Chapter 2:Chapter 2:
The Database DevelopmentThe Database Development
ProcessProcess
Modern Database ManagementModern Database Management
88thth
EditionEdition
Jeffrey A. Hoffer, Mary B. Prescott,Jeffrey A. Hoffer, Mary B. Prescott,
Fred R. McFaddenFred R. McFadden

2© 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

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 high
level of abstractionlevel 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 ArchitectureInformation Systems Architecture
(ISA)(ISA)
 Conceptual blueprint for organization’s desiredConceptual blueprint for organization’s desired
information systems structureinformation systems structure
 Consists of:Consists of:
 Data (e.g. Enterprise Data ModelData (e.g. Enterprise Data Model––simplified ERsimplified ER
Diagram)Diagram)
 ProcessesProcesses––data flow diagrams, processdata 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 projectpeople management using project
management tools (Gantt charts, etc.)management 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)

Information EngineeringInformation Engineering
 A data-oriented methodology to create andA data-oriented methodology to create and
maintain information systemsmaintain information systems
 Top-down planning–a generic IS planningTop-down planning–a 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 entire
organizationorganization
 Four steps to Top-Down planning:Four steps to Top-Down planning:
 PlanningPlanning
 AnalysisAnalysis
 DesignDesign
 ImplementationImplementation

Information Systems PlanningInformation Systems Planning
(Table 2-1)(Table 2-1)
 PurposePurpose––align information technologyalign information technology
with organization’s business strategieswith organization’s 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

Identify Strategic PlanningIdentify Strategic Planning
Factors (Table 2-2)Factors (Table 2-2)
 Organization goals–what we hope toOrganization goals–what we hope to
accomplishaccomplish
 Critical success factors–what MUST workCritical success factors–what MUST work
in order for us to survivein order for us to survive
 Problem areas–weaknesses we now haveProblem areas–weaknesses we now have

Identify Corporate PlanningIdentify Corporate Planning
Objects (Table 2-3)Objects (Table 2-3)
 Organizational units–departmentsOrganizational units–departments
 Organizational locationsOrganizational locations
 Business functions–groups of businessBusiness functions–groups of business
processesprocesses
 Entity types–the things we are trying toEntity types–the things we are trying to
model for the databasemodel for the database
 Information systems–application programsInformation systems–application programs

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

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 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

Example business function-to-Example business function-to-
data entity matrix (Fig. 2-3)data entity matrix (Fig. 2-3)

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

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

(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 Purpose––preliminary understanding
Deliverable––request for study
Database activity––
enterprise modeling
and early conceptual
data modeling

Planning
Analysis
Physical Design
Implementation
Maintenance
Logical Design
Analysis
Purpose–thorough requirements analysis
and structuring
Deliverable–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 structure
Deliverable–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 specifications
Deliverable–program/data
structures, technology purchases,
organization redesigns
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, documenting
Deliverable–operational programs,
documentation, training materials
database implementation,
including coded programs,
documentation,
installation and conversion

Planning
Analysis
Physical Design
Implementation
Maintenance
Logical Design
Maintenance
Purpose–monitor, repair, enhance
Deliverable–periodic audits
database maintenance,
performance analysis
and tuning, error
corrections

Prototyping Database MethodologyPrototyping Database Methodology
(Figure 2.6)(Figure 2.6)

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

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 modeling–drawing entity-relationshipData modeling–drawing entity-relationship
diagramsdiagrams
 Code generation–SQL code for table creationCode generation–SQL code for table creation
 Repositories–knowledge base of enterpriseRepositories–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 datacustomized, and assembled into full-scale data
modelsmodels
 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 relatedProject–a planned undertaking of related
activities to reach an objective that has aactivities 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 ofIncremental commitment–review of
systems development project after eachsystems development project after each
development phase with rejustificationdevelopment phase with rejustification
after each phaseafter each phase

Managing Projects: PeopleManaging 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 SchemaPhysical 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/dataCan 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.)

Chap02: The database Development process

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Chap02: The database Development process