Define the Boyce-Codd Normal Form with instance and also Compare BCNF and 3NF.
Ans: BCNF: For each functional dependency X->Y in a set F of functional dependencies over relation R, either:
- Y is a subset of X or,
- X is a superkey of R
While
3NF: For each functional dependency X->Y in a set F of functional dependencies over relation R, either:
- Y is a subset of X or,
- X is a superkey of R, or
- Y is a subset of K for few key K of R
a. there is no subset of a key is a key