Question 1 |

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 1 Explanation:

Question 2 |

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 2 Explanation:

Question 3 |

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 3 Explanation:

Question 4 |

Considering the following table in a relational database :

\begin{array}{|c|c|c|c|} \hline \text { Last Name } & \text { Rank } & \text { Room } & \text { Shift } \\ \hline \text { Smith } & \text { Manager } & 234 & \text { Morning } \\ \hline \text { Jones } & \text { Custodian } & 33 & \text { Afternoon } \\ \hline \text { Smith } & \text { Custodian } & 33 & \text { Evening } \\ \hline \text { Doe } & \text { Clerical } & 222 & \text { Morning } \\ \hline \end{array}

According to the data shown in the table, which of the following could be a candidate key of the table?

\begin{array}{|c|c|c|c|} \hline \text { Last Name } & \text { Rank } & \text { Room } & \text { Shift } \\ \hline \text { Smith } & \text { Manager } & 234 & \text { Morning } \\ \hline \text { Jones } & \text { Custodian } & 33 & \text { Afternoon } \\ \hline \text { Smith } & \text { Custodian } & 33 & \text { Evening } \\ \hline \text { Doe } & \text { Clerical } & 222 & \text { Morning } \\ \hline \end{array}

According to the data shown in the table, which of the following could be a candidate key of the table?

{Last Name} | |

{Room} | |

{Shift} | |

{Room, Shift} |

Question 4 Explanation:

Question 5 |

What does a data dictionary will identify?

Field name | |

Field format | |

Field types | |

All of the above |

Question 5 Explanation:

Question 6 |

Goals for the design of the logical scheme include

avoiding data inconsistency | |

being able to construct query easily | |

being able to access data efficiently | |

All of the above |

Question 6 Explanation:

Question 7 |

Which of the following is NOT a superkey in a relational schema with attributes
V,W, X, Y, Z and primary key V Y?

VXYZ | |

VWXZ | |

VWXY | |

VWXYZ |

Question 7 Explanation:

Question 8 |

If D_1,D_2,...D_n are domains in a relational model, then the relation is a table, which is a subset of

D_{1} \oplus D_{2} \oplus \cdots \oplus D_{n} | |

D_{1} \times D_{2} \times \cdots \times D_{n} | |

D_{1} \cup D_{2} \cup \cdots \cup D_{n} | |

D_{1} \cap D_{2} \cap \cdots \cap D_{n} |

Question 8 Explanation:

Question 9 |

Let R=(A,B,C,D,E,F) be a relation scheme with the following dependencies C \rightarrow F, E \rightarrow A, EC \rightarrow D, A \rightarrow B. Which of the following is a key of R?

CD | |

EC | |

AE | |

AC |

Question 9 Explanation:

Question 10 |

The maximum length of an attribute of type text is

127 | |

255 | |

256 | |

It is variable |

Question 10 Explanation:

There are 10 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.