DBMS · Question 12 · Hard
Relation R(A, B, C, D) has exactly one candidate key, A. How many superkeys does R have?
- 4
- 16
- 15
- 8
Answer and explanation
Answer: D. 8
Explanation: A superkey is any attribute set containing a candidate key. Every set that contains A is a superkey, and the other three attributes can each be in or out, giving 2^3 = 8 superkeys.
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