Database Journal
MS SQL Oracle DB2 Access MySQL PostgreSQL Sybase PHP SQL Etc SQL Scripts & Samples Links Database Forum

» Database Journal Home
» Database Articles
» Database Tutorials
MS SQL
Oracle
DB2
MS Access
MySQL
» RESOURCES
Database Tools
SQL Scripts & Samples
Links
» Database Forum
» Sitemap
Free Newsletters:
DatabaseDaily  
News Via RSS Feed


follow us on Twitter
Database Journal |DBA Support |SQLCourse |SQLCourse2
 

Featured Database Articles

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



SQL etc Archives

Comment and Contribute

 


(Maximum characters: 1200). You have characters left.

 

 




Latest Forum Threads
SQL etc Forum
Topic By Replies Updated
MySQL rollback UAL225 0 August 21st, 09:56 PM
Complex Search Query Galway 0 May 20th, 10:04 PM
change collation at once supercain 2 May 15th, 06:18 AM
SQL Features, tools and utilities question Neomite 1 April 10th, 09:13 AM