Normal Forms

1-NF:

A relation is said to be in 1-NF if and only if all the values in the relation are atomic and there are no multi valued attributes.

Note: According to CODD’s rule of RDBMS each and every relation shall exist in 1-NF minimum in Relational Database.

2-NF:

A relation is said to be in 2-NF if and only if:

Note: 2-NF eliminates all the partial dependencies hence all the dependencies caused by partial dependencies also gets eliminated.

3-NF:

A relation is said to be in 3-NF if and only if:

  1. It exists in 2-NF
  2. It does not have any Transitive dependencies.

Note: 3-NF eliminates both partial and transitive dependencies and hence the redundancies caused by them would get eliminated.

BCNF (Boyce Codd Normal Form):

A relation is said to be in BCNF if and only if:

  1. It exists in 3-NF.
  2. It does not have any Overlapping candidate key dependencies.

Hierarchy of Normal Forms:

NormalForms

 

 

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