2009年6月16日 星期二

ASSIGNMENT 1: SESSION 5

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.

In our lab exercise, we can see that excepting the supplier number, there are no repeated data between these two tables. All the data are connected with product or suppliers, are divided to products or suppliers table respectively. It is divided your information into subject-based tables to reduce redundant data. It not only reduces the likelihood of errors, but also save the space.


On the others hand, each of the column have a limit type of data. (For example, in the column of product name, it must be a text type. In the column of product cost, it must be a number and dollar types.) If you type a text in the product name column, it will remind you that here cannot support the text data. This function can protect the data more accuracy and integrity.


1 則留言:

  1. Well-written and well-expressed ! I also like the new background color...easier on my eyes. Thanks !

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