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964 database development process intro1

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964 database development process intro1

  1. 1. Chapter 2: The Database Development Process Modern Database Management 7 th Edition Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden
  2. 2. Objectives <ul><li>Definition of terms </li></ul><ul><li>Describe system development life cycle </li></ul><ul><li>Explain prototyping approach </li></ul><ul><li>Explain roles of individuals </li></ul><ul><li>Explain three-schema approach </li></ul><ul><li>Explain role of packaged data models </li></ul><ul><li>Explain three-tiered architectures </li></ul><ul><li>Draw simple data models </li></ul>
  3. 3. Enterprise Data Model <ul><li>First step in database development </li></ul><ul><li>Specifies scope and general content </li></ul><ul><li>Overall picture of organizational data at high level of abstraction </li></ul><ul><li>Entity-relationship diagram </li></ul><ul><li>Descriptions of entity types </li></ul><ul><li>Relationships between entities </li></ul><ul><li>Business rules </li></ul>
  4. 4. Figure 2-1 Segment from enterprise data model (Pine Valley Furniture Company) [simplified E-R diagram, repeat of figure 1.3] Enterprise data model describes the high-level entities in an organization and the relationship between these entities
  5. 5. Information Systems Architecture (ISA) <ul><li>Conceptual blueprint for organization’s desired information systems structure </li></ul><ul><li>Consists of: </li></ul><ul><ul><li>Data (e.g. Enterprise Data Model – simplified ER Diagram) </li></ul></ul><ul><ul><li>Processes – data flow diagrams, process decomposition, etc. </li></ul></ul><ul><ul><li>Data Network – topology diagram (like fig 1.9) </li></ul></ul><ul><ul><li>People – people management using project management tools (Gantt charts, etc.) </li></ul></ul><ul><ul><li>Events and points in time (when processes are performed) </li></ul></ul><ul><ul><li>Reasons for events and rules (e.g. decision tables) </li></ul></ul>
  6. 6. Information Engineering <ul><li>A data-oriented methodology to create and maintain information systems </li></ul><ul><li>Top-down planning: a generic IS planning methodology for obtaining a broad understanding of the IS needed by the entire organization </li></ul><ul><li>Four steps to Top-Down planning: </li></ul><ul><ul><li>Planning </li></ul></ul><ul><ul><li>Analysis </li></ul></ul><ul><ul><li>Design </li></ul></ul><ul><ul><li>Implementation </li></ul></ul>
  7. 7. Information Systems Planning (Table 2-1) <ul><li>Purpose: align information technology with organization’s business strategies </li></ul><ul><li>Three steps: </li></ul><ul><ul><ul><li>Identify strategic planning factors </li></ul></ul></ul><ul><ul><ul><li>Identify corporate planning objects </li></ul></ul></ul><ul><ul><ul><li>Develop enterprise model </li></ul></ul></ul>
  8. 8. Identify Strategic Planning Factors (Table 2-2) <ul><li>Organization goals – what we hope to accomplish </li></ul><ul><li>Critical success factors – what MUST work in order for us to survive </li></ul><ul><li>Problem areas – weaknesses we now have </li></ul>
  9. 9. Identify Corporate Planning Objects (Table 2-3) <ul><li>Organizational units – departments </li></ul><ul><li>Organizational locations </li></ul><ul><li>Business functions – groups of business processes </li></ul><ul><li>Entity types – the things we are trying to model for the database </li></ul><ul><li>Information systems – application programs </li></ul>
  10. 10. Develop Enterprise Model <ul><li>Functional decomposition </li></ul><ul><ul><li>See Figure 2-2 </li></ul></ul><ul><li>Enterprise data model </li></ul><ul><ul><li>See Figure 2-1 </li></ul></ul><ul><li>Planning matrixes </li></ul><ul><ul><li>See Figure 2-3 </li></ul></ul>
  11. 11. 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
  12. 12. Planning Matrixes <ul><li>Describe relationships between planning objects in the organization </li></ul><ul><li>Types of matrixes: </li></ul><ul><ul><li>Function-to-data entity </li></ul></ul><ul><ul><li>Location-to-function </li></ul></ul><ul><ul><li>Unit-to-function </li></ul></ul><ul><ul><li>IS-to-data entity </li></ul></ul><ul><ul><li>Supporting function-to-data entity </li></ul></ul><ul><ul><li>IS-to-business objective </li></ul></ul>
  13. 13. Example business function-to-data entity matrix (Fig. 2-3) Business Planning X X X X Product Development X X X X Materials Management X X X X X X Order Fulfillment X X X X X X X X X Order Shipment X X X X X X Sales Summarization X X X X X Production Operations X X X X X X X Finance and Accounting X X X X X X X X Customer Product Raw Material Order Work Center Work Order Invoice Equipment Employee Business Function (users) Data Entity Types
  14. 14. Two Approaches to Database and IS Development <ul><li>SDLC </li></ul><ul><ul><li>System Development Life Cycle </li></ul></ul><ul><ul><li>Detailed, well-planned development process </li></ul></ul><ul><ul><li>Time-consuming, but comprehensive </li></ul></ul><ul><ul><li>Long development cycle </li></ul></ul><ul><li>Prototyping </li></ul><ul><ul><li>Rapid application development (RAD) </li></ul></ul><ul><ul><li>Cursory attempt at conceptual data modeling. </li></ul></ul><ul><ul><li>Define database during development of initial prototype </li></ul></ul><ul><ul><li>Repeat implementation and maintenance activities with new prototype versions </li></ul></ul>
  15. 15. Systems Development Life Cycle (Figures 2-4, 2-5) Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  16. 16. Systems Development Life Cycle (cont.) (Figures 2-4, 2-5) Maintenance Purpose --preliminary understanding Deliverable –request for project Database activity – enterprise modeling Project Identification and Selection Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  17. 17. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Purpose – state business situation and solution Deliverable – request for analysis Database activity – conceptual data modeling Project Initiation and Planning Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  18. 18. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Purpose – thorough analysis Deliverable – functional system specifications Database activity – conceptual data modeling Analysis Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  19. 19. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Maintenance Purpose – information requirements structure Deliverable – detailed design specifications Database activity – logical database design Logical Design Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  20. 20. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Purpose – develop technology specs Deliverable – program/data structures, technology purchases, organization redesigns Database activity – physical database design Physical Design Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  21. 21. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Purpose – programming, testing, training, installation, documenting Deliverable – operational programs, documentation, training materials Database activity – database implementation Implementation Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  22. 22. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Purpose – monitor, repair, enhance Deliverable – periodic audits Database activity – database maintenance Maintenance Project Identification and Selection Project Initiation and Planning Analysis Physical Design Implementation Maintenance Logical Design
  23. 28. Packaged Data Models <ul><li>Model components that can be purchased, customized, and assembled into full-scale data models </li></ul><ul><li>Advantages </li></ul><ul><ul><li>Reduced development time </li></ul></ul><ul><ul><li>Higher model quality and reliability </li></ul></ul><ul><li>Two types: </li></ul><ul><ul><li>Universal data models </li></ul></ul><ul><ul><li>Industry-specific data models </li></ul></ul>
  24. 29. CASE <ul><li>Computer-Aided Software Engineering (CASE) – software tools providing automated support for systems development </li></ul><ul><li>Three database features: </li></ul><ul><ul><li>Data modeling – entity-relationship diagrams </li></ul></ul><ul><ul><li>Code generation – SQL code for table creation </li></ul></ul><ul><ul><li>Repositories – knowledge base of enterprise information </li></ul></ul>
  25. 30. Managing Projects <ul><li>Project – a planned undertaking of related activities to reach an objective that has a beginning and an end </li></ul><ul><li>Involves use of review points for: </li></ul><ul><ul><li>Validation of satisfactory progress </li></ul></ul><ul><ul><li>Step back from detail to overall view </li></ul></ul><ul><ul><li>Renew commitment of stakeholders </li></ul></ul><ul><li>Incremental commitment – review of systems development project after each development phase with rejustification after each phase </li></ul>
  26. 31. Managing Projects: People Involved <ul><li>Systems analysts </li></ul><ul><li>Database analysts </li></ul><ul><li>Users </li></ul><ul><li>Programmers </li></ul><ul><li>Database/data administrators </li></ul><ul><li>Systems programmers, network administrators, testers, technical writers </li></ul>
  27. 32. Figure 2-8a Gantt Chart Shows time estimates of tasks
  28. 33. Figure 2-8b PERT chart Shows dependencies between tasks
  29. 34. Database Schema <ul><li>Physical Schema </li></ul><ul><ul><li>Physical structures – covered in chapters 5 and 6 </li></ul></ul><ul><li>Conceptual Schema </li></ul><ul><ul><li>E-R models – covered in chapters 3 and 4 </li></ul></ul><ul><li>External Schema </li></ul><ul><ul><li>User Views </li></ul></ul><ul><ul><li>Subsets of Conceptual Schema </li></ul></ul><ul><ul><li>Can be determined from business-function/data entity matrices </li></ul></ul><ul><ul><li>DBA determines schema for different users </li></ul></ul>
  30. 35. Different people have different views of the database…these are the external schema The internal schema is the underlying design and implementation
  31. 36. Figure 2-11 Three-tiered client/server database architecture
  32. 37. Pine Valley Furniture Preliminary data model (Figure 2-12)

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