Chap 1: Database Development Process

Lecture 2: Database Development ProcessISOM3260, Spring 2014

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Where we are nowDatabase environmentintroduction to databaseDatabase development processsteps to develop a databaseConceptual data modelingentity-relationship (ER) diagram; enhanced ERLogical database designtransforming ER diagram into relations; normalizationPhysical database designtechnical specifications of the databaseDatabase implementationStructured Query Language (SQL), Advanced SQLAdvanced topicsdata and database administration

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3Database Development ProcessInformation Systems ArchitectureInformation Systems PlanningSystems Development Life CyclePrototypingPeople involved in database developmentThree-schema database architectureThree-tiered database location architecture

4Information Systems Architecture

5Information Systems Architectureoverall blueprint or plan for an organizations information systemsdeveloped during IS planningconsists ofData (Enterprise Data Model)Processes (that manipulate data, e.g. data flow diagrams)Network (data communication topology diagram)People (perform processes or are source or receiver of data)Events and points in time (when processes are performed)Reasons for events and rules (e.g. decision tables)

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Fig. 1-3: Segment from Enterprise Data Model(shows the high-level entities and their relationships)

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Data Flow Diagram

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Network Diagram

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Decision TableNote: for salaried employees the action stub chosen will always be the sametherefore hours worked is an indifferent condition

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10Decision Tree representation of salary decision

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11Information Systems PlanningAlign IT with the business strategies of the organizationThree steps:Identify strategic planning factorsOrganization goals (what we hope to achieve)Critical success factors (what must work in order to meet the goals)Problem areas (what are the current weaknesses)Identify corporate planning objectsOrganizational units (departments of the organization)Organizational locations (places of operation)Business functions (processes that support the organizations mission)Entity types (data on people, places, and things managed by the organizationInformation systems

12Strategic Planning Factors

13Example: Planning Objects

14Example: Planning Objects (cont.)

15Information Systems Planning (cont.)Develop an enterprise modelFunctional decomposition of business functionsEnterprise data modelEntity-relationship diagramDescriptions of entity typesRelationships between entitiesBusiness rules

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Process decomposition of an order fulfillment function (Pine Valley Furniture)Decomposition -- breaking business functions into smaller tasks in a hierarchical structure chart

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Figure 1-3: Segment from enterprise data modelEnterprise data model describes the entities in an organization and the relationship between these entities

18Approaches to Database DevelopmentSystem Development Life Cycle (SDLC)Detailed, well-planned development processTime-consuming, but comprehensiveLong development cyclePrototypingRapid application development (RAD) methodCursory attempt at conceptual data modelingDefine database during development of initial prototype.Repeat implementation and maintenance activities with new prototype versions

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Database development activities during SDLC

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Figure 1-8: Prototyping methodology and database development process

21People Involved in Database DevelopmentBusiness analysts/Systems analystswork with management and users to analyze information requirementsDatabase analystsconcentrate on requirements and design for databaseUsersprovide assessment of their information needsProgrammersDatabase/Data administratorsOther technical expertssystems programmers, network administrators, testers, technical writers

22Three Schema Architecture for Database DevelopmentAll views of the same databaseConceptual schematechnology independentanalysis phaseExternal schemaone or more user viewseach user view is a subset of conceptual schemalogical design phaseInternal schemaphysical design phasehow data are stored in a computers secondary memory

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Three-schema database architecture

External schemaDifferent people have different views of the databasethese are the external schemaInternal schema

24Process of developing three-schema architecture for a database project

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25Three-Tiered Database Location ArchitectureWhere to store the data during physical database designClient tierpresentation tierdesktop or notebook computer manages user interface and localized dataApplication/Web tierprocess services tierprovides access from client tier to data in enterprise tierEnterprise tierdata services tierminicomputer or mainframe manages organization data

26Figure 1-12: Three-tiered client/server database architecture

27Review QuestionsWhat is an information systems architecture?What are the 3 steps in information systems planning?What are the 3 planning factors?What are the 5 planning objects?What are the two approaches to database development?Who are the people involved in database development?What is the 3-schema database architecture?What is the 3-tiered database location architecture?