What is normalization and differents forms of it?

Posted by silpa on Sep 11 2007

Normalization is a process of efficiently organizing data in the db.
Eliminates redundant data and makes sure that dependencies make sense

different forms are 1NF,2NF,3NF,4NF

1NF
Eliminates duplicate columns
Create separate table for related group of data and identifies each row with unique column called primary key

2NF

Should meet 1NF requirements
Removes sub set of data that apply to multiple rows and places them into new tables
Creates relation bet these new tables and precessing one by a concept called foreign key

3NF

Should meet requirements of 1NF and 2NF
Removes column not dependent on PK

4NF will not have any multi value dependencies

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