In context of databases consider set operations on relation R and S, and…
2022
In context of databases consider set operations on relation R and S, and select a true statement:
- A.
(R − S) ∪ (S − R) = φ
- B.
(R − S) ∪ (S − R) = R ∩ S
- C.
(R − S) ∩ (S − R) = φ
- D.
(R − S) ∪ (S − R) = R ∪ S
Attempted by 308 students.
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Correct answer: C
To evaluate the given statements, consider the set operations on relations R and S. 1. (R − S) represents elements in R but not in S. 2. (S − R) represents elements in S but not in R. 3. (R − S) ∪ (S − R) is the symmetric difference, which includes elements in either R or S but not in both. 4. (R − S) ∩ (S − R) is the intersection of two disjoint sets, so it is always empty. 5. The symmetric difference is not equal to the empty set, intersection, or union unless specific conditions are met.