The questions can come in any order, so make sure you are selecting right option for all questions.
1. Relation R has eight attributes ABCDEFGH. Fields of R contain only atomic values.
F={CH->G, A->BC, B->CFH, E->A, F->EG} is a set of functional dependencies (FDs) so that F + is exactly the set of FDs that hold for R.
How many candidate keys does the relation R have?
(b) 4
2. Consider a relation scheme R = (A, B, C, D, E, H) on which the following functional dependencies hold:
{A —> B, BC ---> D, E, —> C, D —> A}
What are the candidate keys of R?
(d) AEH, BEH, DEH
3. Consider relation R(A,B,C,D,E) with functional dependencies:
AB -> C, C -> D, BD -> E
Which of the following sets of attributes does not functionally determine E?
(b) ACD
4. Let relation R(A,B,C,D,E,F,G,H) satisfy the following functional dependencies:
A -> B, CH -> A, B -> E, BD -> C, EG -> H, DE -> F
Which of the following FDs is also guaranteed to be satisfied by R?
(c) CEG -> AB
5. Consider relation R(A,B,C,D,E) with functional dependencies:
D -> C, CE -> A, D -> A, AE -> D
Which of the following is a key?
(c) BCE
6. The following functional dependencies are given: AB -> CD, AF —> D, DE --> F, C —> G, F —› E, G --> A Which one of the following options is false?
(c) {AE }+ = {ACDEFG}