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

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IS 4420Database FundamentalsChapter 2
Database Development ProcessLeon Chen
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Overview

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

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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

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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
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Information Systems Architecture(ISA)

• Conceptual blueprint for organizations 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)

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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

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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

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Systems Development Life Cycle
Project Identification and Selection
Project Initiation and Planning
Analysis
Logical Design
Physical Design
Waterfall
Implementation
Maintenance
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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
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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
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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
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Entity Relationship Diagram (ERD)
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Systems Development Life Cycle (cont.) (figures
2-4, 2-5)
Purpose information requirements
structure Deliverable detailed design
specifications
Project Identification and Selection
Project Initiation and Planning
Analysis
Logical Design
Physical Design
Database activity logical database design
Implementation
Maintenance
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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
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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
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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
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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
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Different people have different views of the
databasethese are the external schema
The internal schema is the underlying design and
implementation
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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

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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

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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

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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

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Managing Projects People Involved

• Systems analysts
• Database analysts
• Users
• Programmers
• Database/data administrators
• Systems programmers, network administrators,
  testers, technical writers

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Figure 2-8a Gantt Chart
Shows time estimates of tasks
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Figure 2-8b PERT chart (Program Evaluation and
Review Technique)
Shows dependencies between tasks
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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