Union intersection – DBMS
| Question 1 UGC NET June-2020 Match List I with List II let R1 = {(1,1), (2,2), (3,3)} and R2 = {(1,1), (1,2), (1,3), (1,4)}  Choose the correct answer from the options given below: |
| 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)}