Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Chapter: 7
Q121:
Which of the following is an example of a single-valued attribute?
A. Hobbies
B. Skills
C. Employee Name
D. Address
Correct Answer:
C
Chapter: 7
Q122:
What is the purpose of associating a domain with an attribute?
A. To define the operations on the attribute
B. To ensure values are within a specific set or range
C. To give the attribute a unique name
D. To determine the attribute's type
Correct Answer:
B
Chapter: 7
Q123:
An example of a multi-valued attribute is:
A. Employee Name
B. Address
C. Skills
D. Hobby
Correct Answer:
C
Chapter: 7
Q124:
The notation for attribute names generally includes:
A. A full description of the attribute
B. An abbreviation of the entity type and a description of the attribute
C. A unique identifier and a description
D. A random sequence of letters
Correct Answer:
B
Chapter: 8
Q125:
What is an attribute in the context of database systems?
A. A detail that describes the state of an entity
B. A set of keys used to identify an entity
C. A type of entity instance
D. None of the above
Correct Answer:
A
Chapter: 8
Q126:
What is a super key?
A. A set of one or more attributes that can uniquely identify an entity instance
B. A key that is used to access secondary attributes
C. A key that consists of a single attribute only
D. A composite key with multiple attributes
Correct Answer:
A
Chapter: 8
Q127:
Which of the following keys can be used to uniquely identify an entity instance?
A. Candidate Key
B. Secondary Key
C. Foreign Key
D. Alternate Key
Correct Answer:
A
Chapter: 8
Q128:
What is a candidate key?
A. A super key for which no subset is a super key
B. A key that is used to access secondary attributes
C. A key with a single attribute only
D. A key that is defined by the database designer
Correct Answer:
B
Chapter: 8
Q129:
What distinguishes a primary key from other keys?
A. It is chosen by the database designer and cannot be NULL
B. It is always a composite key
C. It is used for secondary access
D. It is a non-key attribute
Correct Answer:
A
Chapter: 8
Q130:
What does a secondary key allow you to do?
A. Access instances based on non-unique attributes
B. Access instances uniquely based on a single attribute
C. Identify entities without using any attributes
D. None of the above
Correct Answer:
A
Chapter: 8
Q131:
Fill in the blank: A __________ key is a candidate key that is not chosen as the primary key.
A. secondary
B. key
C. foreign
D. alternate
Correct Answer:
D
Chapter: 8
Q132:
Fill in the blank: The key that uniquely identifies a single entity instance among many instances is called a __________ key.
A. super
B. candidate
C. primary
D. foreign
Correct Answer:
C
Chapter: 8
Q133:
Which of the following is NOT a type of key mentioned in the content?
A. Primary Key
B. Foreign Key
C. Index Key
D. Secondary Key
Correct Answer:
C
Chapter: 8
Q134:
An attribute that is either required or optional means it:
A. Must always have a value
B. Might or might not have a value
C. Can be empty but must be defined
D. Is always defined as mandatory
Correct Answer:
B
Chapter: 8
Q135:
Which key can consist of one or more attributes but is not necessarily minimal?
A. Primary Key
B. Alternate Key
C. Candidate Key
D. Super Key
Correct Answer:
D
Chapter: 8
Q136:
Fill in the blank: If a composite super key has a subset that can also uniquely identify entity instances, it is called a __________ key.
A. candidate
B. primary
C. secondary
D. foreign
Correct Answer:
A
Chapter: 8
Q137:
Which attribute in the STUDENT entity type is an example of a super key?
A. regNo
B. name
C. phoneNo
D. address
Correct Answer:
A
Chapter: 9
Q138:
What is a relationship in an E-R data model?
A. A connection between entities
B. A type of attribute
C. A unique identifier
D. A data type
Correct Answer:
A
Chapter: 9
Q139:
What does the degree of a relationship refer to?
A. The number of entities involved
B. The number of attributes per entity
C. The uniqueness of entity instances
D. The cardinality of the relationship
Correct Answer:
A
Chapter: 9
Q140:
Which of the following is an example of a binary relationship?
A. Student-Class
B. Student-Student
C. Student-Student-Faculty
D. Student-Class-Faculty
Correct Answer:
A