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Question

Suppose R is a relation schema and F is a set of functional dependencies on R. Further, suppose R1 and R2 form a decomposition of R. Then the decomposition is a lossless join decomposition of R provided that:

a.

R1∩R2→R1 is in F+

b.

R1∩R2→R2 is in F+

c.

both R1∩R2→R1 and R1∩R2→R2 functional dependencies are in F+

d.

at least one from R1∩R2→R1 and R1∩R2→R2 is in F+

Answer: (d).at least one from R1∩R2→R1 and R1∩R2→R2 is in F+

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Q. Suppose R is a relation schema and F is a set of functional dependencies on R. Further, suppose R1 and R2 form a decomposition of R. Then the decomposition is a lossless join...

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