Database Management System
Q21.
Suppose the following functional dependencies hold on a relation U with attributes P, Q, R, S, \text{ and } T: P \rightarrow QR \\ RS \rightarrow T Which of the following functional dependencies can be inferred from the above functional dependencies?[MSQ]Q22.
A database of resear charticles in a journal uses the following schema. Which is the weakest normal form that the new database satisfies,but the old one does not?Q23.
Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?Q24.
Consider the following four relational schemas. For each schema, all non-trivial functional dependencies are listed. The underlined attributes are the respective primary keys. Which one of the relational schemas above is in 3NF but not in BCNF?Q25.
The following functional dependencies hold true for the relational schema R{V,W,X,Y,Z}: V \rightarrowW VW \rightarrowX Y\rightarrow VX Y \rightarrowZ Which of the following is irreducible equivalent for this set of functional dependencies ?Q26.
Let the set of functional dependencies F=\{QR\rightarrow S,R\rightarrow P,S\rightarrow 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?Q27.
For a database relation R(a,b,c,d) where the domain of a,b,c and d include only atomic value, only the following functions dependencies and those that can be inferred from them holda\rightarrowcb\rightarrowdThe relation is in:Q28.
The set of attributes X will be fully functionally dependent on the set of attributes Y if the following conditions are satisfied.Q30.
Every time the attribute A appears, it is matched with the same value of attribute B but not the same value of attribute C. Which of the following is true?