Direction: Consider the following relations A, B and C :
-
How many tuples does the result of the following relational algebra expression contain? Assume that the schema of A ∪ B is the same as that of A.
(A ∪ B)A.ld>40∨C.ld<15C
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- 7
- 4
- 5
- 9
Correct Option: A
A ∪ B will have 5 rows because two rows in B are already in A. When cross product of A ∪ B and C is done, the result is:
The condition is: either A.Id > 40 or C.Id < 15. For first 5 rows, C. Id < 15. For 8th and 10th rows, A. Id > 40. So total rows in result will be 7. So correct option is (A)
