Sunday, 23 February 2014

What are the different type of normalization?

In database design , we start with one single table, with all possible columns. Lot of redundant data would be present since it’s a single table. The process of removing the redundant data, by splitting up the table in a well defined fashion is called normalization.
1. First Normal Form (1NF)


A relation is said to be in first normal form if and only if all underlying domains contain atomic values only. After 1NF , we can still have redundant data
2. Second Normal Form (2NF)


A relation is said to be in 2NF if and only if it is in 1NF and every non key attribute is fully dependent on the primary key. After 2NF , we can still have redundant data
3. Third Normal Form (3NF)


A relation is said to be in 3NF if and only if it is in 2NF and every non key attribute is non-transitively dependent on the primary key 

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