(Choose 1 answer)
When we apply set operators (UNION, INTERSECT, EXCEPT) to two relations R and S, which conditions on R and S must be satisfied?
A. R and S must have schemas with identical sets of attributes and the types (domains) for each attribute must be the same in R and S
B. Before we compute the set-theoretic union, intersection, or difference of sets of tuples, the columns of R and S must be ordered so that the order of attributes is the same for both relations
C. All of the others
Q: 12
