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A functional dependency f on R is _______ by a set of functional dependencies F on r if every instance of r(R) that satisfies f also satisfies F.

A functional dependency f on R is _______ by a set of functional dependencies F on r if every instance of r(R) that satisfies f also satisfies F. Correct Answer Logically implied

Given a set F of functional dependencies on a schema, we can prove that certain other functional dependencies also hold on that schema. We say such FDs are logically implied by F. A functional dependency f on R is logically implied by a set of functional dependencies F on r if every instance of r(R) that satisfies F also satisfies f.

Related Questions

Consider the following four relational schemas. For each schema, all non-trivial functional dependencies are listed. The underlined attributes are the respective primary keys. Schema I: Field ‘courses’ is a set-valued attribute containing the set of courses a student has registered for. Non-trivial functional dependency: rollno → courses Schema II: Non-trivial functional dependencies: rollno, courseid → email email → rollno Schema III: Non-trivial functional dependencies: rollno, courseid → marks, grade marks → grade Schema IV: Non-trivial functional dependencies: rollno, courseid → credit courseid → credit Which one of the relational schemas above is in 3NF but not in BCNF?
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A _________ Fc for F is a set of dependencies such that F logically implies all dependencies in Fc, and Fc logically implies all dependencies in F.
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Let the set of functional dependencies F = {QR → S, R → P, S → Q} hold on a relation schema X = (PQRS). X is not in BCNF. Suppose X is decomposed into two schemas Y and Z, where Y = (PR) and Z = (QRS). Consider the two statements given below. I. Both Y and Z are in BCNF II. Decomposition of X into Y and Z is dependency preserving and lossless Which of the above statements is/are correct?
If a multivalued dependency holds and is not implied by the corresponding functional dependency, it usually arises from one of the following sources.
Given a relation schema R(ABCDEFGH) in first normal form. For the set of dependencies F={ A → B, A → C, CG → H, B → H, G → F}, which dependency is logically implied?
Given an instance of the relation R(ABCD). A B C D a1 b1 c1 d1 a1 b2 c2 d2 a2 b2 c2 d3 a3 b3 c4 d3   Which of the following functional dependencies hold?