Consider a relation R(A, B, C, D, E) with the following three functional
dependencies.

𝐴𝐵 → 𝐶; 𝐵𝐶 → 𝐷; 𝐶 → 𝐸;

The number of superkeys in the relation R is _____________.  

Correct Answer:

8

Solution:

Candidate keys for the given relation R(A, B, C, D, E) is [AB].

So the number of super keys for the given relation R with 5 attributes will be 2(5-2) = 8.

Possible super keys are: [AB, ABC, ABD, ABE, ABCD, ABCE, ABDE, ABCDE]