Third normal form (3NF) deals with the elimination of non-key attributes that do not describe the Primary Key.
For a relation to be in 3NF, the relationship between any two non-Primary Key columns, or groups of columns, in a relation must not be one-to-one in either direction.
We say attributes are mutually independent if none of them is functionally dependent on any combination of the others. This mutual independence ensures that we can update individual attributes without any danger of affecting any other attribute in a row.
The following list of benefits summarizes the advantages of implementing a normalized logical model in 3NF.
- Greater number of relations
- More PI choices
- Optimal distribution of data
- Fewer full table scans