The relational operator union is a Commutative b Associative

The relational operator, union is

a. Commutative

b. Associative

c. both commutative and associative

d. neither commutative nor associative

c. both commutative and associative

UNION operator returns all tuples of relation R1 and R2.

Commutative

R1 UNION R2 and R2 UNION R1 are equivalent .

Associative

R1 UNION(R2 UNION R3) is equivalent to (R1 UNION R2 )UNION R3