Design Objectives Chapter 2
Design Objectives Why should you be concerned with database design? The importance of theory The advantages of learning good design methodology Objectives/advantages of good design Database design methods
Why should you be concerned with database design? Wizards or experts are tools that should be used AFTER the database has been logically designed Database must insure consistency, integrity, and accuracy of data –Inaccurate information is probably the most detrimental result of improper database design. It can adversely affect the bottom line of a business
Importance of theory Most major disciplines have theoretical base –Structural engineers theories of physics –Composers music theory –Automobile designer Aerodynamic theory
Relational Database Models Mathematical theory Guarantees accurate information Guidelines for good design methodologies Not necessary to know all about mathematical theories to use a relational database! Mathematical theories provide the foundation for the relational database model, and thus makes the model predictable, reliable, and sound
Advantages/Objectives of good Design Support required and ad hoc information retrieval Contain efficiently constructed table structures Imposes data integrity at the field, table, and relationship levels Supports appropriate Business Rules Lends itself to future growth
Database design methods Traditional three phase method –Requirements analysis phase examine business being modeled –Data modeling phase modeling the database structure –Normalization phase eliminate redundant data