Can you explain what is meant by the third normal form in a relational database?

The Third Normal Form (3NF) is a database normalization rule that helps eliminate redundancy and update anomalies.

A table is in 3NF if:

1. It is already in the First Normal Form (1NF) — all fields are atomic.
2. It is in the Second Normal Form (2NF) — all non-key attributes depend fully on the primary key.
3. There are no transitive dependencies, meaning non-key fields do not depend on each other, only on the key.

Example:

If there is a table with fields: Student_ID, Student_Name, Department, Department_Name, and Department_Name depends on Department, and Department depends on Student_ID, then this is a transitive dependency. To bring the table to 3NF, a separate table for departments should be created.

Thus, 3NF helps avoid redundant data storage and simplifies data updates.