1.

If a relation with a Schema R is decomposed into two relations R1 and R2 such that (R1 ∪ R2) = R1 then which one of the following is to be satisfied for a lossless joint decomposition (---> indicates functional dependency)

A. (R1 ∩ R2) --> R1 or R1 ∩ R2 ---> R2
B. R1  ∩ R2 --> R1
C. R1∩ R2 --> R2
D. R1 ∩ R2 --> R1 and R1 ∩ R2 --> R2
Answer» B. R1  ∩ R2 --> R1


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