Q20: What is Database Normalization and its forms (1NF, 2NF, 3NF, BCNF)?
Normalization structures database schemas to minimize data redundancy and prevent insertion, update, and deletion anomalies.
- 1NF (First Normal Form): Ensures atomic column values (no multi-valued lists or nested sets) and unique row keys.
- 2NF (Second Normal Form): Satisfies 1NF and removes partial dependencies (non-key attributes must depend on the entire primary key).
- 3NF (Third Normal Form): Satisfies 2NF and removes transitive dependencies (non-key attributes must depend only on primary key attributes).
- BCNF (Boyce-Codd Normal Form): A stricter variant of 3NF where every determinant must be a candidate key.
Key Takeaways
- 1NF enforces atomicity; 2NF removes partial key dependencies; 3NF removes transitive dependencies.
- Higher normalization reduces data redundancy, but can require more JOINs when querying.