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UGC NET CSE | December 2014 | Part 2 | Question: 20

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Identify the minimal key for relational scheme $R(A, B, C, D, E)$ with functional dependencies $F = \left\{A \rightarrow B, B \rightarrow C, AC \rightarrow D\right\}$ 

  1. $A$ 
  2. $AE$
  3. $BE$
  4. $CE$ 

1 Answer

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{A}+={ A , B , C , D }

Here A can not be a key because we can't get attribute E from here.

{AE}+ = { A , B , C , D ,E }

Here AE is the minimal key.We can't remove anything from it.

Hence,Option(B)AE.

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