Online test

Question

Comments

Only (i) is true since conditional join is nothing but imposing condition over the tuples resulted by cross product of relations R and S.

But condition cannot be used with projection operator since it is used to project attributes.

Hence option A) should be true

Answer 1

Option A is correct B/C

JOIN is combination of cross product followed by selection operation

 

B is wrong B/c we didnot filter tuples

C is wrong B/C in Natural join operation( *) number of Attributes is decreased

Comments

I have a doubt about 3rd query. In it rename is used. Now name of attributes of R and S will be different. So will this natural join remove common attributes???

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No,

if renaming is done Natural join is not able to remove common attibute

but in above question there is no selection of tuples

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Thanks.