Question

1. Find the minimal cover of E, where E= { P → QRST, RS → T } (Use Algorithm 15.2)

Answer 1

Please UPVOTE if it helps!!

Steps to find minimal cover :

1) Find Redundancy on Right hand side of functional dependency

2) Find Redundancy on Left hand side of functional dependency

3) Find if the functional dependency is redundant

NOTE :

1) If there is more than one attribute on RHS we will decompose it

2) If there is more than one attribute on LHS it can not be decompose.

3) When we take closure of atrribute for Eg P then we take the atrribute P itself plus set of attributes which are functionally determine by P such as Q ,R ,S ,T.

hence closure(P) = {P,Q,R,S,T }

(In the first image S,T is missing while taking closure of P ,do include that)

4) When we consider closure without taking some functional dependency we don't have to consider RHS of that dependency in closure.

For Eg .If we dont include dependency P -->Q then

closure(P)={P,S,R,T} as we can not generate Q in closure of P without this dependency it is not redundant.