Consider a relation R(A,B,C,D,E) with the following dependencies: {AB-> C, CD -> E, DE -> B} Is AB a candidate key of this relation? If not, is ABD? Explain your answer. No. The closure of AB does not give you all of the attributes of the relation.
If not, is ABD? Explain your answer. A -> A
B -> B
C -> C
D -> D
E -> E
AB -> ABC
AC -> AC
AD -> AD
AE -> AE
BC -> BC
BD -> BD
BE -> BE
CD -> BCDE
CE -> CE
DE -> BDE
ABD -> ABCDE
Yes, ABD is a candidate key. No subset of its attributes is a key.