Suppose there is a relation R(A,B,C,D)

and the dependencies are :

AB->CD
C->B

The relation is not in BCNF if there is a dependency of a proper subset(PS of a candidate key depending on a non key.

Here the candidate keys are AC and AB, so it is like a PS->PS ...so which normal form is it not in

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The question is

Quote:

Here the candidate keys are AC and AB, so it is like a PS->PS ...so which normal form is it not in

Since AB->CD, it is in "AB" form, or "ABnormal form".