IS 4420 Database Fundamentals Chapter 2: Database Development Process Leon Chen 1 Overview       Definition of terms System development life cycle Prototyping approach Three-schema approach Packaged data models Project management 2 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 3 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 4 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) 5 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 6 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 7 Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Analysis Logical Design Physical Design Waterfall Implementation Maintenance 8 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 9 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 Database activity – conceptual data modeling Physical Design Implementation Maintenance 10 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 Database activity – conceptual data modeling Physical Design Implementation Maintenance 11 Entity Relationship Diagram (ERD) 12 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 Database activity – logical database design Physical Design Implementation Maintenance 13 14 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 Database activity – physical database design Physical Design Implementation Maintenance 15 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 Database activity – database implementation Physical Design Implementation Maintenance 16 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 17 Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Database Development Process Enterprise modeling Conceptual data modeling Analysis Logical Design Physical Design Implementation Maintenance Logical database design Physical database design and definition Database implementation Database maintenance 18 19 Different people have different views of the database…these are the external schema The internal schema is the underlying design and implementation 20 Database Schema  Conceptual Schema   Internal Schema    E-R models – covered in chapters 3 and 4 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 21 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 22 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 23 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:      Project management life cycle 1. 2. 3. 4.   Scope Schedule Cost Quality 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 24 Managing Projects: People Involved       Systems analysts Database analysts Users Programmers Database/data administrators Systems programmers, network administrators, testers, technical writers 25 Figure 2-8a Gantt Chart Shows time estimates of tasks 26 Figure 2-8b PERT chart (Program Evaluation and Review Technique) Shows dependencies between tasks 27 Systems Development Life Cycle Project Identification and Selection Project Initiation and Planning Database Development Process Enterprise modeling Conceptual data modeling Analysis Logical Design Physical Design Implementation Maintenance Logical database design Physical database design and definition Database implementation Database maintenance 28