Let R(A, B, C, D, E) be a relation and FD = {AB, DBC, BC D}...

 

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Let R(A, B, C, D, E) be a relation and FD = {AB, DBC, BC D} a set of functional dependencies. Give a sample instance for R on which A→ B does not hold and BCD does not hold. Question 4 [4 points] Let R(A, B, C, D, E, F, G) be a relation and FD = {ABF, BD → C, CA, CF → BE, CE → F} be a set of functional dependencies that hold on R. Give a set of attributes that form a minimal key for R. Explain why your set is a minimal key. Question 5 [4 points] Let R(A, B, C, D, E, F, G) be a relation and FD ={ AB → F, BCE, BD → C, BD → E, C→ A, CEF, FE, } a set of functional dependencies. Is there any functional dependency in FD that is redundant, i.e., it is entailed by the other dependencies in FD? If yes, give an example and explain why it is redundant, if not, explain why none of the functional dependencies in FD are redundant. Let R(A, B, C, D, E) be a relation and FD = {AB, DBC, BC D} a set of functional dependencies. Give a sample instance for R on which A→ B does not hold and BCD does not hold. Question 4 [4 points] Let R(A, B, C, D, E, F, G) be a relation and FD = {ABF, BD → C, CA, CF → BE, CE → F} be a set of functional dependencies that hold on R. Give a set of attributes that form a minimal key for R. Explain why your set is a minimal key. Question 5 [4 points] Let R(A, B, C, D, E, F, G) be a relation and FD ={ AB → F, BCE, BD → C, BD → E, C→ A, CEF, FE, } a set of functional dependencies. Is there any functional dependency in FD that is redundant, i.e., it is entailed by the other dependencies in FD? If yes, give an example and explain why it is redundant, if not, explain why none of the functional dependencies in FD are redundant.

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Question 4 Minimal Key for RA B C D E F G Given the relation R with attributes A B C D E F and G and the set of FDs FD AB F BD C CA CF BE CE F we can ... View the full answer