BCNF

Question

Every BCNF decomposition is

A)Dependency preserving

B)not a dependency preserving

C)Need not be dependency preserving

D)None of the above

Answer 1

Need Not be Dependency Preserving.

Lossless decomposition is the fundamental thing which each and every normalization should follow.

But Preserving dependencies is followed till 2NF,3NF. But when we go for higher normalization like BCNF then  preserving the functional dependencies became difficult since the rule for BCNF are more Strict than 3NF.

Answer 2

Option C is the best ans.
Because in case of BCNF dependency preserving is not necessary . it may be preserved or not.
But in case of 3 nf Dependency preserving is necessary

Answer 3

The answer is c:

Every BCNF decomposition may or may not be dependency preserving

but remember, it will always be lossless decomposition..