What is Normalization?

 Posted by Bama on 5/3/2012 | Category: Sql Server Interview questions | Views: 14028 | Points: 40

Normalization is the process of simplifying the relationship between data elements in a record.

(i) 1st normal form: - 1st N.F is achieved when all repeating groups are removed, and P.K should be defined. big table is broken into many small tables, such that each table has a primary key.
(ii) 2nd normal form: - Eliminate any non-full dependence of data item on record keys. I.e. The columns in a table which is not completely dependent on the primary key are taken to a separate table.
(iii) 3rd normal form: - Eliminate any transitive dependence of data items on P.K’s. i.e. Removes Transitive dependency. Ie If A is the primary key in a table. B & C are columns in the same table. Suppose C depends only on B and B depends on A. Then C does not depend directly on primary key. So remove C from the table to a look up table.

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