R is not the primary key in relation r2 therefore redundant data will result maximum selection of tuples.

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Given R1(P, Q, R) and R2(R ,U, V) where R is primary key in R1 and U is primary key in R2.

R in R1 is primary key so it should contain unique values assume 1,2,3,......1500(1500tuples)

There is no constraint on R in R2 so it can contain duplicate values assume 1,1,1,...1(2000 tuples)

Natural join is performed on the Common attribute i.e R

1 in R( R1 table) can map with 2000 1's in R( R2 table).

Hence maximum 2000 tuples are possible in natural join

R in R1 is primary key so it should contain unique values assume 1,2,3,......1500(1500tuples)

There is no constraint on R in R2 so it can contain duplicate values assume 1,1,1,...1(2000 tuples)

Natural join is performed on the Common attribute i.e R

1 in R( R1 table) can map with 2000 1's in R( R2 table).

Hence maximum 2000 tuples are possible in natural join

0

when 1500 wud be the answer then???

plz check this too. . .https://gateoverflow.in/3553/gate2006-it-14