GATE1999-1.24

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Let $R = (A, B, C, D, E, F)$ be a relation scheme with the following dependencies $C \rightarrow F, E \rightarrow A, EC \rightarrow D, A \rightarrow B $. Which one of the following is a key for $R$?

gate1999
databases
database-normalization
easy

asked Sep 23, 2014 in Databases by Kathleen Veteran (52.2k points) | 872 views

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Best answer

Answer: B

EC is the key for R. Both E and C are not coming on the right hand side of any functional dependency. So, both of them must be present in any key. Now, with EC and the given FDs, we can derive all other attributes making EC a key.

answered May 24, 2015 by Rajarshi Sarkar Boss (33.9k points)
selected Jun 2, 2015 by Rajarshi Sarkar

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