GATE 2013
R (ABCDEFGH)
CH → G
A → BC
B → CFH
E → A
F → EG
Find the number of candidate keys?
Sol. Which one is not at right side.
That is D.
so,
[D]+ → D
Its not candidate key., because not all keys determined in it.
[DA]+ → DABCFHEG
Its candidate key because all keys are determined in it.
[DB]+ → ABCFHEGA
Its candidate key because all keys are determined in it.
[DC]+ → DC
Its not candidate key., because not all keys determined in it.
[DE]+ → DEABCFHG
Its candidate key because all keys are determined in it.
[DF]+ → DFEGABCH
Its candidate key because all keys are determined in it.
[DCH]+ → DCHG
Its not candidate key., because not all keys determined in it.