Union intersection - DBMS

Union intersection – DBMS

A – A-I, B-II, C-IV, D-III

B – A-I, B-IV, C-III, D-II

C – A-I, B-III, C-II, D-IV

D – A-I, B-IV, C-II, D-III

Show Answer With Best Explanation

Answer: D
Explanation:
Union(U):
In set theory, the union (denoted by ∪) of a collection of sets is the set of all elements in the collection.It is one of the fundamental operations through which sets can be combined and related to each other.
R1 U R2 = {(1,1), (1,2), (1,3), (1,4), (2,2), (3,3)}

Set difference:
Set difference is the set of all elements in R1 that are not in R2.
R1 – R2 = {(2,2), (3,3)}
R2 – R1 = {(1,2), (1,3), (1,4)}

Intersection:
Intersection is the set containing all elements of A that also belong to B (or equivalently, all elements of B that also belong to A).
R1∩R2 = {(1,1)}