Chapter Five –Part 2 Database Design.pdf

Information System Management Chapter Five – Part 2: Database Design Dr. Baha’eddin Alhaj Hasan Department of Industrial Engineering  Database Application Systems  Database application consists of:  Forms  Reports  Queries  Application programs How...

Information System Management Chapter Five – Part 2: Database Design Dr. Baha’eddin Alhaj Hasan Department of Industrial Engineering  Database Application Systems  Database application consists of:  Forms  Reports  Queries  Application programs How Are Systems Developed? Figure CE5-1  Database Application System Development Process  Developers interview users  Develop requirements for new system  Analyze existing reports, forms, and user activities  Requirements summarized in data model  Logical representation of structure of data  Contains description of data and relationships  Users validate and approve model  Design implemented in a database  Database filled with user data  Database  Must include all data necessary for users to perform jobs  Contains only that amount of data, and no more  Developers rely on users to:  Tell them what to include  Check data model  Verify correctness and completeness  Database Design  Process of converting data model  Transforms entities into tables  Expresses relationships  Defines foreign keys  Shows data constraints  Normalization  Process  Converts table into two or more tables  Changes from poorly structured to well-structured  Data integrity problems  Different names for the same entity  Produces incorrect and inconsistent information  Resolve by eliminating duplicated data  Normalized tables  Eliminate data duplication  Slower to process  Every table has single topic  Relational Database Design  Designer creates table for every entity  Entity identifier becomes primary key of table  Attributes of entity become columns  Tables normalized to single theme  Represent relationships between tables  Add foreign key to one or more tables  What Is the Users’ Role?  Final judges as to what data should be contained  Determine how records are related to each other  Need to review data model  Must insure that model reflects an accurate view of business  Who Will Volunteer?  Consultant creates data model  Based on interviews with users  Data model reviewed and approved  Database tables constructed  Primary and foreign keys selected  Based on interviews  Microsoft Access database created  Relationships indicated  Forms and reports constructed