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4 Answers

13 votes
13 votes

Answer : C

Third Normal Form but not BCNF

See the dependencies 

AB ---> CDE

C ---> B

C is not a Super key Here

7 votes
7 votes

Answer : C


Dependency: 


AB ---> CDE

C ---> B


1NF(yes): assume all attributes are atomic

2NF(yes): no partial functional  dependency like A alone can derive C or D or E

3NF(yes): no transitive functional dependency or there is nothing like (non key)-->(non key)

BCNF(no): in non trivial FD C-->B  , C is not a SuperKey.


smileyyes

5 votes
5 votes
AB is the key here which determines C ,D E there is no P.D  and T.D between C,D,E SO IT IS IN 3NF

Now for BCNF every determinant is a candidate key determinant here are A,B,C (as C determines B) but C is not  candidate key hence it is not in BCNF (only if C->B is removed it becomes BCNF)

AC is also key  which can determine B and so also  D , E  but B is not candidate key

hence ans is C
edited by
2 votes
2 votes

It is 3NF 

Bcz AB->CDE ,here we can clealy see that AB is super keys that's why it will be in 3NF and BCNF but C->B it is in 3NF not in BCNF that's why we can say that it will be in 3NF not in BCNF bcz both of them should be in BCNF not single one.

Answer:

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