Question

Discuss the union Compatibility for intersection operation of two relations? (4marks)​

Answer 1

Answer:

Explanation:

be union-compatible. 4. INTERSECT: yields only the rows that appear in both tables. As with UNION, the tables must be union-compatible to yield valid ... 2. Operations developed specifically for relational databases—these include SELECT ... In this section we describe a notation typically used in relational systems to ...Two table are said to be union compatible if both the table have same number of attributes (column) and corresponding attributes have the same data type (int,char,float,date etc.). Corresponding attributes means first attributes of both relations, then second and so on.

Answer 2

Answer:

Two relations R(A1, A2, ..., An) and S(B1, B2, ..., Bn) are said to be union compatible (or type compatible) if they have the same degree n and if dom(Ai) = dom(Bi) for 1 ≤ i ≤ n. This means that the two relations have the same number of attributes and each corresponding pair of attributes has the same domain.