Choose all of the correct answers: [a] The number of superkeys of a relation R(A

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Choose all of the correct answers: [a] The number of superkeys of a relation R(A, B, C, D) with keys {A} and {B, C} is 1. 2 2. 10 3. 12 4. All of the above 5. None of the above [b] A relation R 1. Is in BCNF if R is in _3NF 2. Is in _3NF if R is in BCNF 3. Maybe in BCNF but not in _3NF 4. Maybe in _3NF but not in BCNF 5. May be neither in BCF nor in _3NF 6. All of the above 7. None of the above Consider the relation R(A, B, C, D, E) where it is known that the only keys of R are {A, C, D} and {D, E} [a] Give a set of functional dependencies that will make {A, C, D} and {D, E} the only keys of R. This set should be such that if you delete any functional dependency, then the keys of B will be something other than {A, C, D} and {D, E}. [b] Indicate all BCNF and _3NFviolations for the set of functional dependencies in a. [c] Decompose R as necessary into a collection of relations that are in BCNF. Find all projected functional dependencies on each of the decomposed relations of R. [d] Decompose R as necessary into a collection of relations that are in _3NF. Find all projected functional dependencies on each the decomposed relations of R. Consider the following definition of equivalent sets of functional dependencies on a relation: "Two sets of functional dependencies F and F' on a relation R are equivalent if all FD's in F' follow from the ones in F, and all the FD's in F follow from the ones in F'." Given a relation R(A, B, C) with the following sets of functional dependencies:

Explanation / Answer

1.

[a] The number of super keys of relation R(A, B, C, D) with keys {A} and {B, C} is "2"

Ans : 1- 2

[b] A relation R

Ans : 7. None of the above

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