Let R1 (a, b, c) and R2 (x, y, z) be two relations in which a is the foreign key of R1 that refers to the primary key of R2 . Consider following four options. (a)Insert into R 1 (b)Insert into R 2 (c)Delete from R 1 (d)Delete from R 2 Which of the following is correct about the referential integrity constraint with respect to above?

Operations (d) and (a) will cause violation.

Operations (a) and (b) will cause violation.

Operations (b) and (c) will cause violation.

Operations (c) and (d) will cause violation.

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50 DBMS MCQs with Answers

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Question 1

In E-R model, Y is the dominant entity and X is subordinate entity

None of the above
If Y is deleted, then X is also deleted
If Y is deleted, then X is not deleted
If X is deleted, then Y is also deleted

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Question 2

Let R₁ (a, b, c) and R₂ (x, y, z) be two relations in which a is the foreign key of R₁ that refers to the primary key of R₂ . Consider following four options. (a)Insert into R ₁ (b)Insert into R ₂ (c)Delete from R ₁ (d)Delete from R ₂ Which of the following is correct about the referential integrity constraint with respect to above?

Operations (a) and (b) will cause violation.
Operations (b) and (c) will cause violation.
Operations (c) and (d) will cause violation.
Operations (d) and (a) will cause violation.

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Question 3

How to express that some person keeps animals as pets?

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Question 4

A view of database that appears to an application program is known as

Schema
Subschema
Virtual table
Index Table

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Question 5

Which operation is used to extract specified columns from a table?

Project
Join
Extract
Substitute

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Question 6

The relation schemas R₁ and R₂ form a Lossless join decomposition of R if and only if: (a) R₁ ∩ R₂ ↠ (R₁ - R₂) (b) R₁ → R₂ (c) R₁ ∩ R₂ ↠ (R₂ - R₁ ) (d)(R₂ → R₁) ∩ R₂

(a) and (b) happens
(a) and (d) happens
(a) and (c) happens
(b) and (c) happens

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Question 7

In functional dependency Armstrong inference rules refers to

Reflexivity, Augmentation and Decomposition
Transitivity, Augmentation and Reflexivity
Augmentation, Transitivity, Reflexivity and Decomposition
Reflexivity, Transitivity and Decomposition

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Question 8

Which of the following statements is FALSE about weak entity set?

Weak entities can be deleted automatically when their strong entity is deleted.
Weak entity set avoids the data duplication and consequent possible inconsistencies caused by duplicating the key of the strong entity.
A weak entity set has no primary keys unless attributes of the strong entity set on which it depends are included
Tuples in a weak entity set are not partitioned according to their relationship with tuples in a strong entity set.

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Question 9

Relation R has eight attributes ABCDEFGH. Fields of R contain only atomic values. F = {CH -> G, A -> BC, B -> CFH, E -> A, F -> EG} is a set of functional dependencies (FDs) so that F+ is exactly the set of FDs that hold for R. How many candidate keys does the relation R have?

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Question 10

In RDBMS, different classes of relations are created using __________ technique to prevent modification anomalies.

Functional Dependencies
Data integrity
Referential integrity
Normal Forms

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