1,672 views
1 votes
1 votes

 When , then the cost of computing  is

(A)   the same as R  S       

(B)   greater the R  S

(C)    less than R  S                               

(D)    cannot say anything

3 Answers

2 votes
2 votes
(B) greater than R×S

Reason: Every join operation is divided into two parts

First, cross product is calculated.

Second, then the given select conditions are checked. In case of natural join similar name attributes are checked thus increasing the computational cost of it.

CORRECT ME IF I AM WRONG.
1 votes
1 votes

Temp1 ∩ temp2 = Empty

Temp1 × Temp 2 = 3*3 = 9

Temp ⋈ temp2 = 3*3 [cross join operations] +9[checks to match two columns]

It should be greater than   R×S

0 votes
0 votes
my question is this there is no common atrrib between R and S then why natural join operator do comparison and multiply operation.

explain pls!!!
edited by

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