What is Database Normalization? Discuss various types of database Normal Forms?

What is Database Normalization? Discuss various types of database Normal Forms?

Database Normalization is the process to decompose the database and remove the redundancy from the database.

Database Normalization is the formal process for deciding which attributes should be grouped together in a relation. Normalization serves as a tool for validating and improving the logical design, so that the logical design avoids unnecessary duplication of data, i.e. it eliminates redundancy and promotes integrity. In the normalization process we analyze and decompose the complex relations into smaller, simpler and well-structured relations.

The types of database normalization are-

1)1 NF
2)2nd NF
3)3rd NF
4)Boyce codd NF
5)4th NF
6)5th NF

First Normal form (1NF):
A relation is said to be in 1NF if it has only single valued attributes, neither repeating nor arrays are permitted.

Second Normal Form (2NF):
A relation is said to be in 2NF if it is in 1NF and every non key attribute is fully functional dependent on the primary key.

Third Normal Form (3NF):
We say that a relation is in 3NF if it is in 2NF and has no transitive dependencies.

Boyce-Codd Normal Form (BCNF):
A relation is said to be in BCNF if and only if every determinant in the relation is a candidate key.

Fourth Normal Form (4NF):
A relation is said to be in 4NF if it is in BCNF and contains no multi valued attributes.

Fifth Normal Form (5NF):
A relation is said to be in 5NF if and only if every join dependency in relation is implied by the candidate keys of relation.