chapter 10

• Database Systems


  Design, Implementation and Management
• Successful database design must reflect the information system of which the database is a part
• Systems Development Life Cycle (SDLC)


  Framework within which the information system is developed
• Database Life Cycle (DBLC)


  Framework within which the database is subject to frequent evaluation and revision
• Things you will learn in this chapter

  • That successful database design must reflect the information system of which the database is a part
  • That successful information systems are developed within a framework known as the Systems Development Life Cycle (SDLC)
  • That within the information system, the most successful databases are subject to frequent evaluation and revision within a framework known as the Database Life Cycle (DBLC)
  • About common threats to the security of the data and what security measures could be put in place
  • About database design strategies: top-down vs. bottom-up design and centralized vs. decentralized design
  • Of the importance of the database administration in an organization
  • Of the technical and managerial roles of the database administrator (DBA)
• Systems Development Life Cycle (SDLC)


  1. Planning

  2. Analysis

  3. Detailed systems design

  4. Implementation

  5. Operation

  6. Maintenance
• SDLC


  • Traces history (life cycle) of information system
  • Provides "big picture" within which database design and application development can be mapped out and evaluated
  • Iterative rather than sequential process
• Planning phase of SDLC

  1. Initial assessment

  2. Feasibility study
• Analysis phase of SDLC


  1. User requirements

  2. Existing system evaluation

  3. Logical system design
• Design phase of SDLC


  Detailed system specification
• Implementation phase of SDLC


  1. Coding, testing and debugging

  2. Installation, fine-tuning
• Operation phase of SDLC


  1. Produce the required information flow

  2. Help Desk support

  3. Monitoring of performance
• Maintenance phase of SDLC


  1. Evaluation

  2. Maintenance

  3. Enhancement
• Database Initial Study phase of DBLC


  1. Analyze the company situation

  2. Define problems and constraints

  3. Define objectives

  4. Define scope and boundaries
• Database Design phase of DBLC


  1. Create the conceptual design

  2. DBMS software selection

  3. Create the logical design

  4. Create the physical design
• Implementation & Load phase of DBLC

  1. Install the DBMS

  2. Create the databases

  3. Load or convert the data
• Testing & Evaluation phase of DBLC

  1. Test the database

  2. Fine-tune the database

  3. Evaluate the DB and its application programs
• Operation phase of DBLC


  Produce the required information flow
• Maintenance & Evolution phase of DBLC

  1. Introduce changes

  2. Make enhancements
• SDLC and DBLC are related but distinct frameworks
• Analysis


  To break up any whole into its parts so as to find out their nature, function, and so on
• Company situation


  General conditions in which company operates, its organizational structure, and its mission
• Defining problems does not always lead to perfect solutions
• Database system objectives


  Must correspond to those envisioned by end users
• Database Life Cycle (DBLC)


  Traces the history of a database system from its inception to its obsolescence
• The DBLC is concurrent to the Systems Development Life Cycle (SDLC)
• Phases of the DBLC


  • Initial study
  • Design
  • Implementation and loading
  • Testing and evaluation
  • Operation
  • Maintenance and evolution
• SDLC phases


  • Analysis
  • Design
  • Implementation
  • Planning
  • Operation
  • Maintenance
• The database constitutes the core of an information system
• There is no standard measurement for database performance
• Database integrity is enforced through proper use of primary and foreign key rules
• Database backup and recovery procedures create a safety valve, allowing the DBA to ensure the availability of consistent data
• If implementation fails to meet some of system's evaluation criteria, the following can be done: fine-tune specific system and DBMS configuration parameters, modify physical design, modify logical design, upgrade or change DBMS software and/or hardware platform
• Periodic maintenance activities include: preventive maintenance (backup), corrective maintenance (recovery), adaptive maintenance (enhancing performance), assignment of access permissions and their maintenance for new and old users, generation of database access statistics, periodic security audits, periodic system-usage summaries