Question 5 - Assignment One

This week we learned about the basic structure of a relational database design. As a review, read the following short article which I extracted from a Microsoft Access tutorial on the Microsoft Office web site."Relational databases organize data into tables, where each table contains lists of rows and columns similar to a spreadsheet. Each table strictly contains information about one kind of object only.""In a simple database, you might have only one table. For most databases you will need more than one. For example, you might have a table that stores information about products, another table that stores information about orders, and another table with information about customers. In a relational database, we do not mix information about two different objects (e.g. orders and customers) in a single table."


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.
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Labels: ACCESS, Database Design, records, tables


Answer

1. The information of products and suppliers is stored in subject-based tables Products and Suppliers respectively. It eliminate data redundancy in the database.
2. The supplier of a product can be identified since supplier key is stored in the products table.
3. Both of the products and suppliers table can obtain data accuracy once the product information or supplier information are changed since these informations are reference by the key ProductID and Supplier Number respectively.