IS 4420 Database Fundamentals Chapter 2: Database Development Process Leon Chen

1. IS 4420Database FundamentalsChapter 2: Database Development ProcessLeon Chen

2. Overview • Definition of terms • System development life cycle • Prototyping approach • Three-schema approach • Packaged data models • Project management

3. Enterprise Data Model • First step in database development • Specifies scope and general content • Overall picture of organizational data at high level of abstraction • Entity-relationship diagram • Descriptions of entity types • Relationships between entities • Business rules

4. Figure 2-1 Segment from enterprise data model (Pine Valley Furniture Company) Enterprise data model describes the high-level entities in an organization and the relationship between these entities

5. Information Systems Architecture(ISA) • Conceptual blueprint for organization’s desired information systems structure • Consists of: • Data (e.g. Enterprise Data Model – simplified ER Diagram) • Processes – data flow diagrams, process decomposition, etc. • Data Network – topology diagram (like fig 1.9) • People – people management using project management tools (Gantt charts, etc.) • Events and points in time (when processes are performed) • Reasons for events and rules (e.g. decision tables)

6. Information Engineering • A data-oriented methodology to create and maintain information systems • Top-down planning: a generic IS planning methodology for obtaining a broad understanding of the IS needed by the entire organization • Four steps to Top-Down planning: • Planning • Analysis • Design • Implementation

7. Two Approaches to Database and IS Development • SDLC • System Development Life Cycle • Detailed, well-planned development process • Time-consuming, but comprehensive • Long development cycle • Prototyping • Rapid application development (RAD) • Cursory attempt at conceptual data modeling. • Define database during development of initial prototype • Repeat implementation and maintenance activities with new prototype versions

8. Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Waterfall Implementation Maintenance

9. Systems Development Life Cycle (cont.) (Figures 2-4, 2-5) Project Identification and Selection Purpose --preliminary understanding Deliverable –request for project Project Initiation and Planning Analysis Logical Design Physical Design Database activity – enterprise modeling Implementation Maintenance

10. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Project Identification and Selection Purpose – state business situation and solution Deliverable – request for analysis Project Initiation and Planning Analysis Logical Design Physical Design Database activity – conceptual data modeling Implementation Maintenance

11. Systems Development Life Cycle (cont.)(figures 2-4, 2-5) Project Identification and Selection Purpose – thorough analysis Deliverable – functional system specifications Project Initiation and Planning Analysis Logical Design Physical Design Database activity – conceptual data modeling Implementation Maintenance

12. Entity Relationship Diagram (ERD)

13. Systems Development Life Cycle (cont.) (figures 2-4, 2-5) Project Identification and Selection Purpose – information requirements structure Deliverable – detailed design specifications Project Initiation and Planning Analysis Logical Design Physical Design Database activity – logical database design Implementation Maintenance

15. Systems Development Life Cycle (cont.)(figures 2-4, 2-5) Purpose – develop technology specs Deliverable – program/data structures, technology purchases, organization redesigns Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Database activity – physical database design Implementation Maintenance

16. Systems Development Life Cycle (cont.)(figures 2-4, 2-5) Purpose – programming, testing, training, installation, documenting Deliverable – operational programs, documentation, training materials Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Database activity – database implementation Implementation Maintenance

17. Systems Development Life Cycle (cont.)(figures 2-4, 2-5) Project Identification and Selection Purpose – monitor, repair, enhance Deliverable – periodic audits Project Initiation and Planning Analysis Logical Design Physical Design Database activity – database maintenance Implementation Maintenance

18. Systems Development Life Cycle Database Development Process Enterprise modeling Project Identification and Selection Conceptual data modeling Project Initiation and Planning Analysis Logical Design Logical database design Physical database design and definition Physical Design Implementation Database implementation Maintenance Database maintenance

20. Different people have different views of the database…these are the external schema The internal schema is the underlying design and implementation

21. Database Schema • Conceptual Schema • E-R models – covered in chapters 3 and 4 • Internal Schema • Logical schema – covered in chapters 5 • Physical schema – covered in chapters 6 • External Schema • User Views • Subsets of Conceptual Schema • Can be determined from business-function/data entity matrices • DBA determines schema for different users

22. Packaged Data Models • Model components that can be purchased, customized, and assembled into full-scale data models • Advantages • Reduced development time • Higher model quality and reliability • Two types: • Universal data models • Industry-specific data models

23. CASE • Computer-Aided Software Engineering (CASE) – software tools providing automated support for systems development • Three database features: • Data modeling – entity-relationship diagrams • Code generation – SQL code for table creation • Repositories – knowledge base of enterprise information

24. Managing Projects • Project – a planned undertaking of related activities to reach an objective that has a beginning and an end • Project management is a balance of: • Scope • Schedule • Cost • Quality • Project management life cycle • Initiation • Planning and scheduling • Control • Closing • Project management tool: Microsoft Project • Incremental (creeping) commitment – review of systems development project after each development phase with rejustification after each phase

25. Managing Projects: People Involved • Systems analysts • Database analysts • Users • Programmers • Database/data administrators • Systems programmers, network administrators, testers, technical writers

26. Figure 2-8a Gantt Chart Shows time estimates of tasks

27. Figure 2-8b PERT chart (Program Evaluation and Review Technique) Shows dependencies between tasks

28. Systems Development Life Cycle Database Development Process Enterprise modeling Project Identification and Selection Conceptual data modeling Project Initiation and Planning Analysis Logical Design Logical database design Physical database design and definition Physical Design Implementation Database implementation Maintenance Database maintenance