minimal cover

Question

Comments

yes, sandeep  PQ -> R must be there,    but It can be merged with PQ -> T

so, it becomes PQ -> RT

---

yes, sorry , i read wrong fds , i solved PQ-->P , :P

---

Then what's the ans 4 or 5?

Answer 1

Answer will be 5 here .... 

here you will got very nice explaination to find minimal cover... go through this steps and answer will be 5 only.

https://gateoverflow.in/11276/find-minimal-cover-from-given-functional-dependencies

Answer 2

Nonsense question

Minimal covers are not unique and minimal cover never means that no of FDs will be least.It just means that the obtained FD sets are irreducible

Answer 3

no this is wrong answer =>only thing we can do here is apply union rule last

PQ->R &  PQ->T    ==== PQ->RT

answer is 4 but nothing is extraneous here

Answer 4

The given FD’s are itself the minimal cover, as we don't have any extraneous attributes. so can’t remove any FD from it. 

Just apply the union rule :

To compute a canonical cover for F: repeat Use the union rule to replace any dependencies in F α1 → β1 and α1 → β2 with α1 → β1 β2

 If we apply union rule we get answer 4. otherwise answer will be 5.