ISI-2017 C3 (a)

Question

Let R(A,B,C) be a relation with primary key (A) and S(A,D,E) a relation with primary key (A,D). Each of the relations has n tuples. If the number of tuples in R natural join S is m, then determine the number of tuples in R natural left outer join S.

Comments

maximum no of tuples???

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This was the question given i just copied it. I don't have the solution nor the answer.

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ok

i think it  should be maximum otherwise answer is varies according to question.

Answer 1

first row  of relation R is join with each row's with relation S. then we get maximum tuples.

Comments

This is wrong It depends on the number of distinct values in column A of Table S that have joined with column A of table R. Let this value be Nd. Then ans: (n - Nd) + m.