Question

If the following in BCNF, if not normalize the FDs

A-> B

B-> C

C-> EDB

D -> E

E -> CD

Answer 1

The super key for given functional dependencies will be A, AC, AB, AD, AE, ABC, ABD, ABE, ACD, ACE, ADE etc

candidate key will be A.

for a FD a->b to be in BCNF a must be superkey and it should be in 3NF

In the above given functional dependencies only A -> B has superkey on left side, so it is in BCNF

In B -> C, not in 3NF as it holds transitive dependency but it is in 2NF as it is not partial dependency

In C -> EDB, it is also in 2NF

similarly, D->E and E->CD is also in 2NF. as the left hand side is not part of candidate key and this is not a case of partial dependecy.

So tables/relations formed will be

R1(AB), fd- A->B

R2(BC), fd- B->C

R3(CEDB), fd- C->EDB

R4(DE), fd- D->E

R5(ECD), fd- E->CD

all of them is in BCNF now