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Question

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: (a).(R1 ∩ R2) --> R1 or R1 ∩ R2 ---> R2

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Q. 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...

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