"There are two basic principles behind relational database design. The first principle is that duplicate information (also called redundant data) is bad, because it wastes space and increases the likelihood of errors and inconsistencies. The second principle is that the correctness and completeness of information is important. If your database contains incorrect information, any reports that pull information from the database will also contain incorrect information. As a result, any decisions you make that are based on those reports will then be misinformed."
"A good database design is, therefore, one that:
* Divides your information into subject-based tables to reduce redundant data.
* Provides the database management system (e.g. ACCESS) with the information it requires to join the information in the tables together as needed.
* Helps support and ensure the accuracy and integrity of your information.
* Accommodates your data processing and reporting needs."
(Reference: http://office.microsoft.com/en-us/access/HA012242471033.aspx?pid=CH100645691033#Good)Think of the small database we used in our lab exercise - Products and Suppliers. Briefly describe how this database observes any two of the four design principles outlined above.
Ans:
Just visiting !
回覆刪除