NORMAL FORMS II

CONTENT

• Problems of Table in First Normal Forms
• Determinant of Normal Forms

Problems of Table in First Normal Forms

The basic problem is that department names and addresses are really data about departments rather than employees and belong to a separate Department table. We, therefore, establish a third table for department data, resulting in the three-table model below.

Employee Table

Department Table

Qualification Table

We leave the Department number in the Employee table to serve as a cross-reference, in the same way, that we retained the Employee Number in the Qualification table. Our data is now normalized.

Determinant of Normal Forms

It is important to understand that this whole procedure of separating hospital data relied on the fact that for a given hospital number there could be only one hospital name, contact person, hospital type and teaching status. In fact, we could look at the dependency of hospital data on hospital numbers as the cause of the problem. Every time a particular hospital number appeared in the Operation table, the hospital name, contact person, hospital type and teaching status were the same.