Need help on Functions Dependency problems, Urgent!!!

I'm a newbie on function dependency problem, currently working on the following questions, but havn't got a clue. Anyone can solve this will be highly apprieciated.

F = {A->B, C->D, AC->E, B->E, CE->A, BD->C} is a set of function dependencies on S (ABCDEF)

1. Find all the candidate keys of S regarding to F.
2. Find a cover for F+|ABCD, F+ is the closure of F.
3. Find a BCNG and loss less join decomopsetion for S. explain the procedure
4. Does the BCNF and loss less join decomposition in (3) preserve the set F of fd's?

Anyone can figure out these?
THX. Received on Sun Nov 10 2002 - 22:12:41 CST