What are different normalization forms?

1NF: Eliminate Repeating Groups Make a separate table for every set of related attributes, and give each table a primary key. Each field contains at most one value from its attribute domain.

2NF: Eliminate Redundant Data If an attribute depends on only part of a multi-valued key, remove it to a separate table.

3NF: Eliminate Columns Not Dependent on Key if attributes do not contribute to a explanation of the key; remove them to a separate table. All attributes must be directly dependent on the primary key.

BCNF: Boyce-Codd Normal Form If there are non-trivial dependencies among candidate key attributes, separate them out into distinct tables.

4NF: Isolate Independent Multiple Relationships No table may contain two or more 1: n or n: m relationships that are not directly related.

5NF: Isolate Semantically Related Multiple Relationships There may be practical constrains on information that justify separating logically related many-to-many relationships.