union:
the term of the relation as performed by combining the tuples from one
relation with those a second relation to produce a third
relation.duplicate tuples are eliminated.the the relation must be union
compatable.
difference:
the difference of two relations is a third relation having tuples that occur in
the first relation but not in the second relation.
intersection:
the intersection operation selects the common tuples from the two relations.
cartesian product:
the cartesian product of two relations is the concatination of tuples belonging
to the two relations.a new resultant scheme is created consisting of
concatination of all possible combination of tuples.
