Database-Management-System

Question 358

Let R = (A, B, C, D, E, F) be a relation schema with the following dependencies:

C → F,E → A, EC → D, A → B

Which of the following is a key for R?

Database-Management-SystemFunctional-DependencyTNPSC-2012-Polytechnic-CS

Question 358 Explanation:

Let’s find closure of each options,
(CD)⁺ = CDF X
(EC)⁺ = ECFDAB ✓
(AE)⁺ = AEB X
(AC)⁺ = ACBF X

Correct Answer: B

Question 358 Explanation:

Let’s find closure of each options,
(CD)⁺ = CDF X
(EC)⁺ = ECFDAB ✓
(AE)⁺ = AEB X
(AC)⁺ = ACBF X