Suppose that we have the following three tuples in a legal instance of a relation

schema S with three attributes ABC (listed in order) : (1,2,3), (4,2,3), and (5,3,3).

Which of the following dependencies can you infer does not hold over schema S?

(a) A - > B, (b) BC - > A, (c) B - > C

(b) BC → A

Explanation:

For given instance of S, certain dependencies (that is to say, A → B and B → C) can be said that they are not violated by this instance of S.

It can be said that an FD holds with respect to a relationship is to make a claim about all appropriate instances of S.

BC → A does not hold over S. To confirm, let's look at the tuples (1, 2, 3) and (4, 2, 3).

Hence, the answer is (b) BC → A.