Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Chapter: 9
Q141:
What type of relationship involves three entities?
A. Unary relationship
B. Binary relationship
C. Ternary relationship
D. N-ary relationship
Correct Answer:
C
Chapter: 9
Q142:
Which symbol indicates total participation in an ER diagram?
A. Single line
B. Double line
C. Dotted line
D. Dashed line
Correct Answer:
B
Chapter: 9
Q143:
A relationship where entities link to themselves is called a ________ relationship.
A. Binary
B. Unary
C. Ternary
D. N-ary
Correct Answer:
B
Chapter: 9
Q144:
In an E-R diagram, what does a diamond represent?
A. An attribute
B. A relationship
C. A key
D. A role
Correct Answer:
B
Chapter: 9
Q145:
What is an example of a unary relationship?
A. Student-Class
B. Employee-Project
C. Student-Roommate
D. Student-Faculty
Correct Answer:
C
Chapter: 9
Q146:
In a one-to-many mapping, how are entities in X and Y related?
A. Each entity in X maps to many entities in Y, and each entity in Y maps to one entity in X
B. Each entity in X maps to one entity in Y, and each entity in Y maps to many entities in X
C. Each entity in X maps to many entities in Y, and each entity in Y maps to many entities in X
D. Each entity in X maps to one entity in Y, and each entity in Y maps to one entity in X
Correct Answer:
A
Chapter: 9
Q147:
A ________ key can have multiple attributes.
A. Primary
B. Secondary
C. Foreign
D. Candidate
Correct Answer:
C
Chapter: 9
Q148:
Which of the following relationships is characterized by entities interacting with themselves?
A. Binary
B. Unary
C. Ternary
D. N-ary
Correct Answer:
B
Chapter: 9
Q149:
In a many-to-many relationship, how many entities from X are associated with entities from Y?
A. Each entity from X is associated with many entities in Y, and vice versa
B. Each entity from X is associated with one entity in Y, and vice versa
C. Each entity from X is associated with many entities in Y, and each entity in Y is associated with one entity in X
D. Each entity from X is associated with one entity in Y, and each entity in Y is associated with many entities in X
Correct Answer:
A
Chapter: 9
Q150:
The cardinality of a relationship describes the ________.
A. Number of entities in a relationship
B. Number of attributes in a relationship
C. The optionality of the relationship
D. The roles involved in the relationship
Correct Answer:
A
Chapter: 9
Q151:
Fill in the blank: The ________ relationship is an abstraction of a relationship and includes a set of relationship instances sharing common attributes.
A. specific
B. entity
C. type
D. relationship
Correct Answer:
B
Chapter: 9
Q152:
Fill in the blank: In an ER diagram, the continuous line connecting diamonds to rectangles indicates the ________ of the relationship.
A. optional
B. mandatory
C. role
D. participation
Correct Answer:
B
Chapter: 9
Q153:
Fill in the blank: A ________ key is chosen by the database designer to act as the primary means of identifying entity instances.
A. super
B. secondary
C. candidate
D. foreign
Correct Answer:
C
Chapter: 10
Q154:
What does the minimum cardinality indicate in an ER model?
A. Maximum number of instances
B. Minimum number of instances
C. Optional or compulsory link
D. Number of entities
Correct Answer:
C
Chapter: 10
Q155:
In a one-to-many relationship, what does "one" represent?
A. One entity on both sides
B. One entity on one side and many on the other
C. Many entities on both sides
D. Many entities on one side and one on the other
Correct Answer:
B
Chapter: 10
Q156:
Which notation is used to represent cardinalities in ER diagrams with arrows?
A. Crow's foot notation
B. Arrow-head notation
C. Alphabetical notation
D. Dot-based notation
Correct Answer:
B
Chapter: 10
Q157:
What type of relationship is described when an entity is associated with itself?
A. Binary relationship
B. Unary relationship
C. Ternary relationship
D. N-ary relationship
Correct Answer:
B
Chapter: 10
Q158:
What does "existence dependency" imply in an ER model?
A. Entity instances are optional
B. Entity instances must exist in both entities
C. Entity instances must exist in one entity
D. Entity instances are not linked
Correct Answer:
C
Chapter: 10
Q159:
How is a role in a recursive relationship typically represented?
A. By connecting different entity types
B. By labeling lines with roles
C. By using multiple relationships
D. By showing cardinalities
Correct Answer:
B
Chapter: 10
Q160:
Which dependency type involves a key from a parent entity used in a dependent entity?
A. Identifier dependency
B. Referential dependency
C. Existence dependency
D. Foreign key dependency
Correct Answer:
B