Relation R is decomposed using a set of functional dependencies, F, and relation S is decomposed using another set of functional dependencies, G. One decomposition is definitely BCNF, the other is definitely 3NF, but it is not known which is which. To make a guaranteed identification, which one of the following tests should be used on the decompositions? (Assume that the closures of F and G are available).
A) False. BCNF may or may not satisfy Dependency preservation, 3NF always does. But we can't make any guaranteed decision, regarding BCNF if it satisfies Dependency preservation
B) False. Both are lossless.
C) True. Using this we can always decide between BCNF & 3NF.
D) False. Every BCNF relation is also 3NF trivially.
ANswer -> C ( & Only C)
BCNF may or may not preserve dependency preservation. 3NF satisfy dependency preservation. Both BCNF and 3NF are Lossless join decomposition. So we BCNF definition is required.
Answer is C. BCNF definition