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Database Systems: Design, Implementation, and Management

Database Systems: Design, Implementation, and Management. Chapter 9 Database Design. The Systems Development Life Cycle ( SDLC ). Traces history (life cycle) of information system Database design and application development mapped out and evaluated Iterative rather than sequential process.

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Database Systems: Design, Implementation, and Management

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  1. Database Systems: Design, Implementation, and Management Chapter 9 Database Design

  2. The Systems Development Life Cycle (SDLC) • Traces history (life cycle) of information system • Database design and application development mapped out and evaluated • Iterative rather than sequential process

  3. JMSB BTM and the SDLC Entire SDLC BTM Minor

  4. Technology Acceptance Model http://www.istheory.yorku.ca/Technologyacceptancemodel.htm Davis, F. D. (1989). Perceived usefulness, perceived ease of use, and user acceptance of information technology. MIS Quarterly, 13(3), 319-339.

  5. Two fundamental issues in deciding how much functionality to implement in a new system • How much functionality should you implement? (Perceived Usefulness) • Baseline replication: The new system must at least be as functional as the old one • User-requested functionality: The system should add new features required by users • Analyst-suggested functionality: The system may optionally go beyond users’ expectations • How much retraining effort would it take users to learn to use the new system? (Perceived Ease of Use) • Baseline replication:Minimal effort, or net zero effort (takes no more effort than time and effort saved from switching from old system) • User-requested functionality: Users must feel that new retraining is worthwhile considering the benefits they have asked for • Analyst-suggested functionality:No extra retraining should be required, unless users are absolutely convinced of benefits of extended functionality

  6. The Database Life Cycle (DBLC) • Six phases: • Database initial study • Database design • Implementation and loading • Testing and evaluation • Operation • Maintenance and evolution

  7. Conceptual Design • Creating a detailed, validated ERD • Independent of RDBMS chosen

  8. DBMS Software Selection • Critical to information system’s smooth operation • Common factors affecting purchasing decisions: • Cost • DBMS features and tools • Underlying model • Portability • DBMS hardware requirements • http://en.wikipedia.org/wiki/Comparison_of_relational_database_management_systems

  9. Logical Design • Specifying the tables, attributes and keys • Specifying the domain integrity and attribute constraints • Dependent on chosen RDBMS

  10. Physical Design • Dependent on chosen hardware

  11. Top-down versus bottom-updatabase design strategies • Top-down design • Identifies groups of entities • Defines data elements for each of those groups • Definition of different entity types • Definition of each entity’s attributes • Bottom-up design • Identifies data attributes (items) • Groups them together into entities, and then larger groups

  12. Centralized vs. decentralized design • Centralized design • When data component is composed of small number of objects and procedures • Typical of small systems • Decentralized design • Data component has large number of entities • Complex relations on which complex operations are performed • Problem is spread across several operational sites

  13. Sources • Most of the slides are adapted from Database Systems: Design, Implementation and Management by Carlos Coronel and Steven Morris. 11th edition (2015) published by Cengage Learning. ISBN 13: 978-1-285-19614-5 • Other sources are noted on the slides themselves

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