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We can use the following three rules to find logically implied functional dependencies. This collection of rules is called

We can use the following three rules to find logically implied functional dependencies. This collection of rules is called Correct Answer Armstrong’s axioms

By applying these rules repeatedly, we can find all of F+, given F.

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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?
The _______ is a set of all functional and multi values dependencies implied by a set of functional dependencies
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.
The following functional dependencies hold true for the relational schema R{V, W, X, Y, Z}: V → W VW → X Y → VX Y → Z Which of the following is irreducible equivalent for this set of functional dependencies?
Relation R with an associated set of functional dependencies, F, is decomposed into BCNF. The redundancy (arising out of functional dependencies) in the resulting set of relations is
In the following questions are to be based on the details given below. A salesman visits 274 houses in a town to find out the views about three products X, Y and Z. He found that 157 use X, 98 use only X, 22 use all the three, 14 use X and Z but not Y, 39 use Y and Z, 48 use only Y. How many use product Z only?
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?
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.
In the following questions are to be based on the details given below. A salesman visits 274 houses in a town to find out the views about three products X, Y and Z. He found that 157 use X, 98 use only X, 22 use all the three, 14 use X and Z but not Y, 39 use Y and Z, 48 use only Y. Which product is the most popular one?
In the following questions are to be based on the details given below. A salesman visits 274 houses in a town to find out the views about three products X, Y and Z. He found that 157 use X, 98 use only X, 22 use all the three, 14 use X and Z but not Y, 39 use Y and Z, 48 use only Y. What fraction used at least two products?