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SQL etc

Posted Mar 22, 2002

Database Normalization - Page 5

By Ian Gilfillan

A table is in 2nd normal form if
it's in 1st normal form
it includes no partial dependencies (where an attribute is dependent on only a part of a primary key).

So, we go through all the fields. Project name is only dependent on Project number. Employee name, Rate category and Hourly rate are dependent only on Employee number. So we remove them, and place these fields in a separate table, with the key being that part of the original key they are dependent on. So, we are left with the following 3 tables:

Employee project table

Project number - primary key
Employee number - primary key

Employee table

Employee number - primary key
Employee name
Rate category
Hourly rate

Project table

Project number - primary key
Project name

The table is now in 2nd normal form. Is it in 3rd normal form?

Database Normalization: Part 6

 » See All Articles by Columnist Ian Gilfillan

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