# Give all the functional dependencies that violate 3nf

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Unformatted text preview: Give all the functional dependencies that violate 3NF, and justify your answer. Answer: The only candidate key of R is AC. A B violates 3NF, because A is not a super key and B is not part of the candidate key AC. D F violates 3NF, because D is not a super key and F is not part of the candidate key AC. Q.5 [5 pts] Given two relation schemas: R(A, B) with functional dependency A and S(B, C) with functional dependency B C. State whether the result of (R in BCNF. Justify your answer. B, S) is Answer: The result of (R S) which will have the functional dependencies A B and B C. The resulting relation.is not in BCNF, because for B C, B is not a super key of that relation. Q.6 [25 pts] Consider the relation schema R(X, Y, Z, W) with the following set of functional dependencies: {XY Z, XY W, Z X, W Y} (a) [5 pts] List the candidate key(s) of R. (b) [10 pts] State whether R is in 3NF or not, and why. If it is not, decompose it into 3NF relations. (c) [10 pts] State whether R is in BCNF or not, and why. If it is not, decompose it into BCNF relations. Answer: (a) Candidate keys: XY, YZ, ZW, XW. (b) R is in 3NF. For XY Z, XY is a super key. For XY W, XY is a super key. For Z X, Z is not a super key but X is part of a candidate key. Fo...
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