Which normalization form ensures every functional dependency is a dependency on a superkey?

Which normalization form ensures every functional dependency is a dependency on a superkey?

• A. BCNF (Boyce-Codd Normal Form)
• B. 3NF (Third Normal Form)
• C. 4NF (Fourth Normal Form)
• D. 2NF (Second Normal Form)

Answer: (A)

BCNF requires that every nontrivial functional dependency has a left side that is a superkey. In other words, if X determines Y, X must be able to determine all attributes of the relation. This strict rule prevents dependencies that arise from non-key attributes governing other attributes, which helps eliminate update anomalies. This is stricter than 3NF, which allows some dependencies with non-superkey determinants if the dependent attribute is part of a candidate key. 4NF deals with multi-valued dependencies, not the left-side key requirement. 2NF focuses on removing partial dependencies on a candidate key, not on ensuring every dependency has a superkey. So, the form that enforces every functional dependency to be a dependency on a superkey is BCNF.

BCNF requires that every nontrivial functional dependency has a left side that is a superkey. In other words, if X determines Y, X must be able to determine all attributes of the relation. This strict rule prevents dependencies that arise from non-key attributes governing other attributes, which helps eliminate update anomalies. This is stricter than 3NF, which allows some dependencies with non-superkey determinants if the dependent attribute is part of a candidate key. 4NF deals with multi-valued dependencies, not the left-side key requirement. 2NF focuses on removing partial dependencies on a candidate key, not on ensuring every dependency has a superkey. So, the form that enforces every functional dependency to be a dependency on a superkey is BCNF.