GATE | GATE-CS-2005 | Question 30
Let r be a relation instance with schema R = (A, B, C, D). We define r1 = ΠA, B, C (r) and r2 = ΠA.D (r). Let s = r1 * r2 where * denotes natural join. Given that the decomposition of r into r1 and r2 is lossy, which one of the following is TRUE?
(A) s ⊂ r
(B) r ∪ s
(C) r ⊂ s
(D) r * s = s
Explanation: See Question 1 of https://www.geeksforgeeks.org/database-management-systems-set-10/
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