Question

Suppose we are given a database with a table T with attributes (M, N, P, Q, R) and a set of functional dependencies F = {MQ ->R, MR -> P, RP ->Q, P -> Q }. With an example explain Third form of Normalization.

Answer 1

Given,

Functional dependencies $F = \{MQ\rightarrow R, MR \rightarrow P, RP \rightarrow Q, P \rightarrow Q \}.$

$\{MQ\}+=\{MQ\}$

$=\{MQR\}$ trivial dependencies $(MQ\rightarrow R)$

$=\{MPQR\}$ trivial dependencies $(MR\rightarrow P)$

Hence MQ is the candidate key