Question 1 |

Which one of the options given below refers to the degree (or arity) of a relation in
relational database systems?

Number of attributes of its relation schema. | |

Number of tuples stored in the relation. | |

Number of entries in the relation. | |

Number of distinct domains of its relation schema. |

Question 1 Explanation:

Question 2 |

Consider a relation R( A, B, C, D, E ) with the following three functional dependencies.

AB \rightarrow C;BC \rightarrow D; C \rightarrow E;

The number of superkeys in the relation R is .

AB \rightarrow C;BC \rightarrow D; C \rightarrow E;

The number of superkeys in the relation R is .

12 | |

8 | |

6 | |

5 |

Question 2 Explanation:

Question 3 |

Consider the following statements S1 and S2 about the relational data model:

S1: A relation scheme can have at most one foreign key.

S2: A foreign key in a relation scheme R cannot be used to refer to tuples of R.

Which one of the following choices is correct?

S1: A relation scheme can have at most one foreign key.

S2: A foreign key in a relation scheme R cannot be used to refer to tuples of R.

Which one of the following choices is correct?

Both S1 and S2 are true | |

S1 is true and S2 is false | |

S1 is false and S2 is true | |

Both S1 and S2 are false |

Question 3 Explanation:

Question 4 |

Consider the relation R(P,Q,S,T,X,Y,Z,W) with the following functional dependencies.

PQ\rightarrow X;\quad P\rightarrow YX;\quad Q\rightarrow Y; \quad Y\rightarrow ZW

Consider the decomposition of the relation R into the constituent relations according to the following two decomposition schemes.

D1:\quad R=[(P,QS,T);\;(P,T,X);\;(Q,Y);\;(Y,Z,W)]

D2:\quad R=[(P,Q,S);\;(T,X);\;(Q,Y);\;(Y,Z,W)]

Which one of the following options is correct?

PQ\rightarrow X;\quad P\rightarrow YX;\quad Q\rightarrow Y; \quad Y\rightarrow ZW

Consider the decomposition of the relation R into the constituent relations according to the following two decomposition schemes.

D1:\quad R=[(P,QS,T);\;(P,T,X);\;(Q,Y);\;(Y,Z,W)]

D2:\quad R=[(P,Q,S);\;(T,X);\;(Q,Y);\;(Y,Z,W)]

Which one of the following options is correct?

D1 is a lossless decomposition, but D2 is a lossy decomposition. | |

D1 is a lossy decomposition, but D2 is a lossless decomposition. | |

Both D1 and D2 are lossless decompositions. | |

Both D1 and D2 are lossy decompositions. |

Question 4 Explanation:

Question 5 |

Immunity of the external schemas (or application programs) to changes in the conceptual scheme is referred to as:

Physical Data Independence | |

Logical Data Independence | |

Both (A) and (B) | |

None of the above |

Question 5 Explanation:

There are 5 questions to complete.

Options are wrong in question no 18

Thank You PRAFUL SAMBHAJI RANE,

We have updated this question.

qestion no 15 ans is incorrect

Ans is correct.

Ans is correct use 2^n-1 for single attribute candidate key, use (2^n-1+2^n-1-2^n-2) for double attribute candidate key