Basic relational theory help

My professor and my TA skipped their office hours and Im totally lost. Can someone give me a hand? They also rarely respond to emails. Just looking for guidance since Im confused.

Consider relation schema R(A,B,C) and the set of functional dependencies
F={B->A,A->C}

1. All non-trivial relations. Is this correct? Im just guessing. B->A, A->C,B->C,AB->BC,AC->C, BC->CA,AB->C
2. Find a non-empty instsance of R(give a number of rows) that satisfies every Functional Dependency in F. Is this correct? A B C 2 1 3 3 2 4 4 3 5
3. Find an instance in R that satisfies every FD in F accept A->B

How do you get A->B???? I dont see it.

4. Possible to find an instance an instance that satisfies every FD in F, but does not satisfy the FD AB->C. I have no idea. Im totally lost.

Can someone point in the right direction? Received on Mon Nov 17 2003 - 16:47:34 CST