I have a few database questions over functional dependency and he did not cover these very well in class....I really do not understand how this concept works whatsoever... one of my questions is:

Let R be a relation with n attributes. What is the max # of functional dependencies R can possibly satisfy? (Trivial as well as nontrivial)? Justify your answer.

* I believe the answer would be n since they can all be trivial n=n dependencies but I am not sure if that is correct...


Also,

Prove Darwen's "General Unification Theorm". Clearly indicate which rule applies to each step of your proof.

Google them. First hit on each question.

I figured them out. But I'm utterly confused on these...we went over FDs but only for a minute or 2 in lecture and he gave us a huge assignment on this crap...


Show all work/explanations if possible.


Relation R{A,B,C,D,E,F} satisfies the following FDs:

AB->C
C->A
BC->D
ACD->B
BE->C
CE->FA
CF->BD
D->EF

Find an irreducible equivalent for this set of FDs.



Also,


Relation R{A,B,C,D,E,F,G,H,I,J} satisfies the following FDs:

ABD->E
AB->G
B->F
C->J
CJ->I
G->H

Is this an irreducible set? What are the candidate keys?