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1-
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Which one of the following is correct?
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A -
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All functional dependencies are many-to-many relationships.
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B -
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All functional dependencies are many-to-one relationships.
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C -
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All functional dependencies are one-to-one relationships.
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D -
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None of the above are true.
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2-
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Given the functional dependencies (AB -> C, C -> D) for the relation schema R(ABCD), the
dependency A -> D can be inferred by
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A -
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the reflexive rule
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B -
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the augmentation rule
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C -
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the transitve rule
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D -
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None of the above
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3-
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Given the set of functional dependencies, (AB -> CDE and A -> E), for relation scheme R =
(A,B,C,D,E) we can infer the following:
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A -
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A is a key for R
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B -
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BE is a key for R
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C -
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AB is a key for R
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D -
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None of the above
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4-
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If AB -> CD is one of the functional dependencies, which hold for relation schema R(A,B,C,D), then
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A -
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AB is a key for R
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B -
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no two tuples in R can have the same values for A and B
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C -
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AB is a primary key for R
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D -
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All of the above
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5-
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The functional dependency A -> B for relation schema R(A,B,C,D) implies that
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A -
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no two tuples in R can have the same value for attribute B
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B -
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no two tuples in R can have the same value for attribute A
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C -
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any two tuples in R that have the same value for B must have the same value for A
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D -
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any two tuples in R that have the same value for A must have the same value for B
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6-
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Given only the relation scheme Books(Title,Author,Year,Publisher), we can infer the following
functional dependency
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A -
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Author,Publisher -> Publisher
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B -
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Title -> Author
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C -
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Year -> Publisher
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D -
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Author -> Publisher
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7-
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A relation schema R is in 3rd normal form if
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A -
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each nonprime attribute in R is fully dependent on every key
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B -
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All attributes in R have atomic domains
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C -
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R satisfies 2nd normal form and no nonprime attribute of R is transitively dependent on the primary key
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D -
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R contains only 3 keys
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8-
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Which of the following is a correct statement with respect to relations and keys?
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A -
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if a set of attributes is a superkey then it is always a key
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B -
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if a set of attributes is a superkey then every subset is a key
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C -
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if a set of attributes is a key then it is also a superkey
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D -
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All of the above
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9-
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Consider a relation R(A,B,C,D,E) with the following functional dependencies: ABC -> DE and D ->
AB.
The number of superkeys of R is:
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A -
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10
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B -
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11
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C -
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12
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D -
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6
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10-
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If field A is functionally dependent on field B, then which of the following is true?
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A -
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For every value of field B there can be many possible value of field B.
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B -
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For every value of field B there can be only one possible value of field A.
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C -
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For every value of field A there can be only one possible value of field B.
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D -
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None of the others.
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