IS 4420 Database Fundamentals Chapter 2: Database Development Process

IS 4420 Database Fundamentals Chapter 2: Database Development Process

IS 4420
Database Fundamentals
Chapter 2:
Database Development Process
Leon Chen
1
Overview
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Definition of terms
System development life cycle
Prototyping approach
Three-schema approach
Packaged data models
Project management
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Enterprise Data Model
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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)
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Conceptual blueprint for organization’s desired
information systems structure
Consists of:
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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
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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:
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Planning
Analysis
Design
Implementation
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Two Approaches to Database
and IS Development
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SDLC
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System Development Life Cycle
Detailed, well-planned development process
Time-consuming, but comprehensive
Long development cycle
Prototyping
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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
Database activity –
conceptual data modeling
Physical Design
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
Database activity –
conceptual data modeling
Physical Design
Implementation
Maintenance
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Entity Relationship Diagram (ERD)
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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
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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
Database activity –
physical database design
Physical 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
Database activity –
database implementation
Physical Design
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
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
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Different people
have different
views of the
database…these
are the external
schema
The internal
schema is the
underlying
design and
implementation
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Database Schema
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Conceptual Schema
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Internal Schema
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E-R models – covered in chapters 3 and 4
Logical schema – covered in chapters 5
Physical schema – covered in chapters 6
External Schema
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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
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Model components that can be purchased,
customized, and assembled into full-scale data
models
Advantages
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Reduced development time
Higher model quality and reliability
Two types:
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Universal data models
Industry-specific data models
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CASE
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Computer-Aided Software Engineering (CASE) –
software tools providing automated support for
systems development
Three database features:
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Data modeling – entity-relationship diagrams
Code generation – SQL code for table creation
Repositories – knowledge base of enterprise
information
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Managing Projects
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Project – a planned undertaking of related activities to
reach an objective that has a beginning and an end
Project management is a balance of:
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Project management life cycle
1.
2.
3.
4.
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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
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Managing Projects:
People Involved
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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
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
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