Database Management System MCQs with Answers
Practice important Database Management System MCQs with answers and explanations.
Multiple Choice Questions
Q251: What property of relational algebra allows expressions to be nested and used iteratively?
- A: Closure
- B: Union
- C: Selection
- D: Projection
View Answer
A
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
View Answer
B
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
View Answer
A
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
View Answer
A
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
View Answer
A
Q256: What symbol denotes the Select operation in relational algebra?
- A: π
- B: σ
- C: ∪
- D: ∩
View Answer
B
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
View Answer
A
Q258: In relational algebra, which operation is represented by the symbol ∏?
- A: Select
- B: Project
- C: Union
- D: Set Difference
View Answer
B
Q259: Which operator is used to perform a cross product in relational algebra?
- A: ∪
- B: σ
- C: ×
- D: ∩
View Answer
C
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
View Answer
A