Question 1 |

In a relational data model, which one of the following statements is TRUE?

A relation with only two attributes is always in BCNF. | |

If all attributes of a relation are prime attributes, then the relation is in BCNF. | |

Every relation has at least one non-prime attribute. | |

BCNF decompositions preserve functional dependencies. |

Question 1 Explanation:

Question 2 |

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?

P \rightarrow QR \\ RS \rightarrow T

Which of the following functional dependencies can be inferred from the above functional dependencies?

**[MSQ]**PS \rightarrow T | |

R \rightarrow T | |

P \rightarrow R | |

PS \rightarrow Q |

Question 2 Explanation:

Question 3 |

If every non-key attribute functionally dependent on the primary key, then the relation will be in

First normal form | |

Second normal form | |

Third normal form | |

Fourth Normal form |

Question 3 Explanation:

Question 4 |

Consider a relational table R that is in 3NF, but not in BCNF. Which one of the following statements is TRUE?

R has a nontrivial functional dependency X\rightarrow A, where X is not a superkey and A is a prime attribute. | |

R has a nontrivial functional dependency X\rightarrow A, where X is not a superkey and A is a non-prime attribute and X is not a proper subset of any key. | |

R has a nontrivial functional dependency X\rightarrow A, where X is not a superkey and A is a non-prime attribute and X is a proper subset of some key. | |

A cell in R holds a set instead of an atomic value. |

Question 4 Explanation:

Question 5 |

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?

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?

Both I and II | |

I only | |

II only | |

Neither I nor II |

Question 5 Explanation:

Question 6 |

The set of attributes X will be fully functionally dependent on the set of attributes Y if the following conditions are satisfied.

X is functionally dependent on Y | |

X is not functionally dependent on any subset of Y | |

Both (A) and (B) | |

None of these |

Question 6 Explanation:

Question 7 |

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 hold

a\rightarrowc

b\rightarrowd

The relation is in:

a\rightarrowc

b\rightarrowd

The relation is in:

First normal form but not in second normal form | |

Second normal form but not in third normal form | |

Third normal form | |

None of the above |

Question 7 Explanation:

Question 8 |

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?

Which one of the relational schemas above is in 3NF but not in BCNF?

Schema I | |

Schema II | |

Schema III | |

Schema IV |

Question 8 Explanation:

Question 9 |

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 ?

V \rightarrowW

VW \rightarrowX

Y\rightarrow VX

Y \rightarrowZ

Which of the following is irreducible equivalent for this set of functional dependencies ?

V \rightarrowW V\rightarrowX Y \rightarrowV Y \rightarrowZ | |

V \rightarrowW W \rightarrowX Y\rightarrow V Y\rightarrow Z | |

V \rightarrowW V\rightarrow X Y\rightarrow V Y \rightarrowX Y \rightarrowZ | |

V \rightarrowW W\rightarrow X Y\rightarrow V Y \rightarrowX Y \rightarrowZ |

Question 9 Explanation:

Question 10 |

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?

Which is the weakest normal form that the new database satisfies,but the old one does not?

1NF | |

2NF | |

3NF | |

BCNF |

Question 10 Explanation:

There are 10 questions to complete.

Sir, Please check question number 24. Half question is something else, and half is something else.

Thank You Ashutosh,

We have updated the question.

Ques 2’s answer should be option c. kindly check and confirm.

https://www.geeksforgeeks.org/isro-isro-cs-2020-question-65/

Answer is (B) only. You can check the details solution.

In Question Number 34, there is printing mistake in ( A→→BC )

The correct option is : i) if A→→B and A→→C then A→BC

Thank You Rashmi,

We have updated the option. It is question no 28.

Question 45.

3rd option is:-

AB→C, C→AD

Please update it ;-).

In question number 24 there is a problem in defining relational schema.

plz correct 46 it is a msq