Database Management Systems

1
(No Transcript)
2
Database Management Systems

• MIS 421
• Dr. Steven C. Ross
• 2002

3
Part I The Context of Database Management

• The Database Environment
• role of databases in organizations
• classifications of databases
• database vs. file management
• Database Development Process
• part of the SDLC
• user/analyst interaction
• information engineering and enterprise data model
• ?

4
Chapter 1 The Database Environment
5
Evolution

• Data keyed in at run time
• INPUT statements
• Data stored in the program
• DATA and READ statements
• Data stored in program-specific files
• FORMAT and READn statements
• Data stored in program-independent files
• DBMS software
• ?

6
Data Access

• Delimited
• 97071,Smith,Joe,Woodburn,OR,35.9597754,Kleindiens
  t,Arthur,Prineville,OR,2998.47
• Fixed
• 97071Smith Joe Woodburn OR
  35.9597754Kleindienst Arthur Prineville
  OR2998.47
• ?

7
Terminology

• Data
• Information
• Metadata
• ?

8
Disadvantages of Traditional File Systems

• Program-data dependence
• Data redundancy duplication
• Limited data sharing
• Excessive programming and maintenance effort
• Poor data control homonyms, synonyms
• Inadequate data manipulation capabilities
• ?

9
The Database Approach

• Enterprise data model
• high-level entities and associations among them
• model of organization
• integration of data and processes
• Relational databases
• data should be related through natural, logical
  relationships inherent in the data
• tables relations made up of rows and columns
• Database applications
• Create Read Update Delete
• ?

10
The Range of Database Applications

• Personal computer databases
• one user, PC or PDA, megabytes of data
• Workgroup databases
• 5?25 users, server, mega-gigabytes
• Department databases
• 25?100 users, servers, gigabytes
• Enterprise databases
• gt100 users, servers, giga-terabytes
• Internet
• gt1000, web servers, mega-gigabytes
• ?

11
Advantages of the Database Approach

• Program-data independence
• Minimal data redundancy
• Improved data consistency
• Improved data sharing
• Increased productivity of development staff
• Enforcement of standards
• Improved data quality
• Improved data accessibility
• Reduced program maintenance
• but ...

12
Cautions, Costs, and Risks

• 6Ps Prior planning prevents pretty poor
  performance
• New, specialized personnel needed
• Costly and complex to install and manage
• Costly to convert
• Backup and recovery more important
• Organizational/social issues
• ?

13
Components of the Database Environment

• See Figure 1-10
• CASE Tools
• Repository
• Database Management System (DBMS)
• Database
• Application Programs
• User Interface
• Data Administrators
• System Developers
• End Users
• ?

14
Chapter 2 Database Development Process
15
The Information Systems Architecture

• Data enterprise data model (E-R diagram)
• Processes data flow diagrams
• Network schematic diagram
• People context diagram, other DFDs
• Events state transition diagrams
• Reasons decision tables, repository entries
• ?

16
Information Engineering

• Planning
• Analysis
• Design
• Implementation
• ?

17
Information Systems Planning

• Step 1 Identify strategic planning factors
• goals what we want to achieve
• critical success factors things we must
  accomplish if we are to succeed
• problem areas known weaknesses
• ?

18
Information Systems Planning

• Step 2 Identify corporate planning objects
• organizational units how the people (and
  resources) are organized
• organizational locations where they work
• business functions what they do
• entity types what they keep track of
• information systems existing or proposed systems
• ?

19
Information Systems Planning

• Step 3 Develop an enterprise model
• functional decomposition diagram(s)
• enterprise data model
• matrices matrixes
• location by function
• unit by function
• information system by data entity
• function by data entity
• information system by objective
• ?

20
Strategic Database Planninganother way of
looking at the issues

• Five year plan
• information needs of the functional areas
• information needs of the levels of management
• information needs of geographical locations
• model of the information needs
• anticipated data volumes by location
• preliminary estimate of costs
• recommendations for detailed development
• ?

21
The SDLC

• Project identification and selection
• Project initiation and planning
• Analysis
• Logical design
• Physical design
• Implementation
• Maintenance
• ?

22
Database Development during the SDLC

• Project identification and selection enterprise
  modeling
• Project initiation and planning Analysis
  conceptual data modeling
• Logical design logical database design
• Physical design physical database design and
  creation
• Implementation database implementation
• Maintenance database maintenance
• ?

23
Rapid Application Development

• Prototyping
• identify problem
• develop initial prototype
• implement and use prototype
• ??
• revise and enhance prototype
• convert to operational system
• ?

24
CASE and Repository

• Drawing
• Code generation
• Repository
• ?

25
Three-Level Database Architecture

• See Figure 2-8
• External level
• Analysis phase
• users
• Conceptual level
• Analysis Logical Design phases
• systems analysts
• Internal level
• Physical Design phase
• database programmers/specialists
• ?

26
Three-Tiered Database Location Architecture

• See Figure 2-10
• Client tier
• Department tier
• Enterprise tier
• ?

27
(No Transcript)