Third Normal Form (3NF)


Third Normal Form is the final step of basic normalization.

A table must already be in Second Normal Form.

3NF removes transitive dependency.

Transitive dependency occurs when a non-key column depends on another non-key column.

This creates indirect dependency.

In 3NF, non-key columns must depend only on the primary key and nothing else.

This ensures clean table structure.

Here, dept_name depends on dept_id, not directly on emp_id.

This violates Third Normal Form.

Third Normal Form removes transitive dependency.

It creates a clear relationship between tables.

3NF produces well-structured databases.