Consider the relations r1(P, Q, R) and r2(R, S, T) with primary keys P and R respectively. The relation r1 contains 2000 tuples and r2 contains 2500 tuples. The maximum size of the join r1⋈ r2 is equal to r2⋈ r1 true or false?

https://gateoverflow.in/176728/relational-algebra

how ans is 2000

because there is noting specify about foreign key constraint ,then how we assume that r1.R is always a subset of r2.R .

ANSWER:FOR THIS OF QUESTION CHECK THE COMMON ATTRIBUTE THEREFORE IT WILL PRINT ONLY 2000 TUPLES.

AND VICE VERSA YOU CAN CHECK

TAKE A SAMPLE TABLE EXAMPLE.

TABLE R1

P

Q

R

1

3

2

..

2000

TABLE R2

S

T

2500

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