Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Chapter: 15
Q241:
Multi-valued attributes in a relational database are represented by _______.
A. A single relation containing all values
B. Two relations: one for the entity type and one for the multi-valued attribute
C. One relation with a composite attribute
D. Attributes with default values
Correct Answer:
B
Chapter: 16
Q242:
What is the primary focus of mapping relationships in a database?
A. Identifying primary keys
B. Establishing relationships between entity types
C. Defining attributes
D. Normalizing data
Correct Answer:
B
Chapter: 16
Q243:
In a one-to-many relationship, how is the relationship implemented in the relational model?
A. By placing the primary key of the many-side entity as a foreign key in the one-side entity
B. By placing the foreign key of the one-side entity in the many-side entity
C. By creating a new table for the relationship
D. By combining the primary keys of both entities
Correct Answer:
B
Chapter: 16
Q244:
What does the cardinality of a relationship describe?
A. The number of attributes in a relation
B. The number of rows in a relation
C. The number of instances in each participating entity type
D. The number of relations in the database
Correct Answer:
C
Chapter: 16
Q245:
In a one-to-one relationship, what is typically included in the optional side?
A. The primary key of the compulsory side as a foreign key
B. The primary key of the optional side as a foreign key
C. A composite key from both sides
D. A unique constraint from both sides
Correct Answer:
A
Chapter: 16
Q246:
Which type of relationship involves creating a third table to manage the relationship between two entities?
A. One-to-Many
B. One-to-One
C. Many-to-Many
D. Unary
Correct Answer:
C
Chapter: 16
Q247:
In the given example of the BOOK and STD entities, what is the purpose of the TRANS table?
A. To store details of book borrowers and return dates
B. To store book details and student details
C. To manage the relationship between books and students
D. To keep track of book authors and titles
Correct Answer:
C
Chapter: 16
Q248:
What is the minimum cardinality of a foreign key if an entity can exist without being linked to another entity?
A. Zero
B. One
C. Two
D. Three
Correct Answer:
A
Chapter: 16
Q249:
What is the main difference between procedural and non-procedural data manipulation languages?
A. Procedural languages require a method of how to perform operations, while non-procedural languages only specify what to do
B. Both types of languages perform the same operations, but non-procedural languages are more efficient
C. Procedural languages are used for defining data structures, while non-procedural languages are used for querying data
D. Non-procedural languages do not support data manipulation operations
Correct Answer:
A
Chapter: 16
Q250:
Which of the following is NOT one of the basic operations in relational algebra?
A. Selection
B. Projection
C. Join
D. Cartesian Product
Correct Answer:
C
Chapter: 16
Q251:
What property of relational algebra allows expressions to be nested and used iteratively?
A. Closure
B. Union
C. Selection
D. Projection
Correct Answer:
A
Chapter: 16
Q252:
What does the term 'degree' of a relation refer to?
A. The number of tuples in the relation
B. The number of attributes in the relation
C. The number of relations in the database
D. The number of primary keys in the relation
Correct Answer:
B
Chapter: 16
Q253:
What is typically transformed into a relation when mapping a one-to-many relationship?
A. The primary key of the one-side entity is included as a foreign key in the many-side entity
B. The foreign key of the many-side entity is included in the one-side entity
C. A composite key is created for both entities
D. A new table is created for the relationship
Correct Answer:
A
Chapter: 16
Q254:
In the context of relational algebra, what is the output of the union operation?
A. A new relation that contains all tuples from both input relations, without duplicates
B. A new relation that contains only tuples present in both input relations
C. A new relation that contains tuples present in one input relation but not the other
D. A new relation that contains only distinct tuples from both input relations
Correct Answer:
A
Chapter: 17
Q255:
What are the two broad categories of relational algebra operations?
A. Unary and Binary
B. Select and Project
C. Union and Intersection
D. Set Difference and Cartesian Product
Correct Answer:
A
Chapter: 17
Q256:
What symbol denotes the Select operation in relational algebra?
A. π
B. σ
C. ∪
D. ∩
Correct Answer:
B
Chapter: 17
Q257:
What is the primary purpose of the Union operation in relational algebra?
A. To combine tuples from two relations without duplication
B. To find common tuples between two relations
C. To select specific tuples from a relation
D. To eliminate duplicates within a single relation
Correct Answer:
A
Chapter: 17
Q258:
In relational algebra, which operation is represented by the symbol ∏?
A. Select
B. Project
C. Union
D. Set Difference
Correct Answer:
B
Chapter: 17
Q259:
Which operator is used to perform a cross product in relational algebra?
A. ∪
B. σ
C. ×
D. ∩
Correct Answer:
C
Chapter: 17
Q260:
What is the outcome of the Intersection operation between two union-compatible relations?
A. A set of tuples found in both relations
B. A set of tuples found in either relation
C. A set of tuples in the first relation but not in the second
D. All tuples in both relations
Correct Answer:
A