Verma Ashish yes right !!

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2 votes

Consider relation ‘*R’* and *‘S*’ have *‘n’* and ‘*m*’ tuples, respectively. Choose the best matching between **List-I (Expression) **and **List-II (Maximum number of tuple):**

Soln. According to me Answer should be Option C.

1.R union S = m+n (easy nothing to say)

2. Say Relations are like:- R(A,B,C) s(C,D)

R S

A B C C D

1 2 3 3 4

2 3 3 3 5

4 3 3 3 6

Now in R natual join S = m * n

So option C should suffice isn't it ?

0 votes

**d** is Right answer

. **P- 4 **is obvious so no need to explain this.

**Q – 3 **because natural join compare the common attribute so the best case would be- all of matches the condition and combine **min(m,n)** since all tuples are matching extra number of tuples in either of relation will be discarded

**R – 2 explanation -** because for maximum number of tuple the best case would be – that all tuples in R satisfy the given condition and then got cross product with S and we know that number of tuples in cross product **m x n**

**S – 1 **the best case for maximum tuples would be if nothing get minus or discarded from relation **R with n tuples **so max tuples = n

0 votes

The answer will be option “d” as the question has asked about the maximum number of tuples.

In option R, if the condition is satisfied by all the tuples of relation R then maximum number can be m*n.

In option Q, the minimum of R,S is found, as first cartesian product is done and then common tuples are shown.

In option R, if the condition is satisfied by all the tuples of relation R then maximum number can be m*n.

In option Q, the minimum of R,S is found, as first cartesian product is done and then common tuples are shown.