MCQ – Chapter 3 - 4
1. What does the relational model use to represent data?
A. Trees
B. Graphs
C. Tables
D. Objects
Answer: C
2. What is a tuple in the relational model?
A. A column in a table
B. A row in a table
C. A key in a table
D. A schema in a database
Answer: B
3. What is a primary key?
A. A unique identifier for a table
B. A secondary identifier for a table
C. An attribute that can be null
D. A foreign key reference
Answer: A
4. What is the formal term for a column in a relational table?
A. Tuple
B. Domain
C. Attribute
D. Key
Answer: C
5. What is the relational schema?
A. A diagram of table relationships
B. A description of tables in a database
C. The actual data in a table
D. The primary key of a table
Answer: B
6. What does entity integrity ensure?
A. Referential integrity is maintained
B. No duplicate rows exist
C. Primary key cannot be null
D. Foreign key references are valid
Answer: C
7. What constraint requires that all values in a column must be unique?
A. Domain constraint
B. Entity integrity constraint
C. Key constraint
D. Referential integrity constraint
Answer: C
8. What type of constraint ensures that a foreign key must match a primary
key in another table?
A. Domain constraint
B. Entity integrity constraint
C. Key constraint
D. Referential integrity constraint
Answer: D
9. What is a domain in the context of relational databases?
A. A set of permissible values for an attribute
B. A unique identifier for a table
C. A set of tuples in a table
D. A schema of the database
Answer: A
10. What action does the CASCADE option specify in referential integrity
constraints?
A. Reject the deletion
B. Set the foreign key to NULL
C. Propagate the change
D. Perform no action
Answer: C
11. What does the RESTRICT option do in the case of a DELETE operation?
A. Propagates the deletion
B. Sets the foreign key to NULL
C. Rejects the deletion
D. Updates the foreign key
Answer: C
12. What is the purpose of a relational database schema?
A. To describe the structure of a database
B. To manage user access
C. To store actual data
D. To enforce security policies
Answer: A
13. Which operation might violate a key constraint?
A. INSERT
B. DELETE
C. UPDATE
D. SELECT
Answer: A
14. What term describes a special value used to represent unknown or
inapplicable information?
A. Default value
B. Null value
C. Placeholder
D. Key value
Answer: B
15. Which of the following is NOT an update operation in a relational
database?
A. INSERT
B. DELETE
C. MODIFY
D. SELECT
Answer: D
16. Which of the following constraints is automatically enforced by the
DBMS?
A. Key constraint
B. Business rule
C. Trigger
D. Stored procedure
Answer: A
17. What is a foreign key?
A. A primary key in the same table
B. An attribute in one table that is a primary key in another
C. A unique identifier for a database
D. A schema-level constraint
Answer: B
18. What type of constraint is violated if an attribute value is not within its
domain?
A. Key constraint
B. Domain constraint
C. Referential integrity constraint
D. Entity integrity constraint
Answer: B
19. Which operation can cause a referential integrity violation?
A. INSERT
B. DELETE
C. SELECT
D. MODIFY
Answer: B
20. What does the acronym SQL stand for?
A. Structured Question Language
B. Simple Query Language
C. Structured Query Language
D. Standard Query Language
Answer: C
21. What is the result of a violation of the entity integrity constraint?
A. Duplicate primary key values
B. Null value in a primary key column
C. Foreign key mismatch
D. Attribute value out of domain
Answer: B
Chapter 4
22. What is an Entity in an ERD?
A. A relationship between data
B. A uniquely identifiable object
C. A type of data structure
D. A primary key
Answer: B
23. Which symbol represents a weak entity in an ERD?
A. Double oval
B. Diamond
C. Double rectangle
D. Single rectangle
Answer: C
24. What type of attribute can have multiple values?
A. Composite attribute
B. Simple attribute
C. Multivalued attribute
D. Derived attribute
Answer: C
25. In an ERD, which of the following represents a relationship?
A. Ellipse
B. Rectangle
C. Diamond
D. Line
Answer: C
26. What is the primary purpose of an ERD?
A. To define the logical structure of a database
B. To create a database
C. To manage data in a database
D. To physically implement a database
Answer: A
27. Which of the following is an example of a derived attribute?
A. Name
B. Date of Birth
C. Age
D. Social Security Number
Answer: C
28. What is the symbol for a weak relationship?
A. Double diamond
B. Single diamond
C. Dashed line
D. Bold line
Answer: A
29. Which attribute uniquely identifies each entity in an entity set?
A. Composite attribute
B. Multivalued attribute
C. Key attribute
D. Derived attribute
Answer: C
30. What does a double line indicate in an ERD?
A. Total participation
B. Partial participation
C. Multivalued attribute
D. Composite attribute
Answer: A
31. Which type of attribute is represented by an oval in an ERD?
A. Simple attribute
B. Composite attribute
C. Multivalued attribute
D. Derived attribute
Answer: A
32. What is a relationship set in an ERD?
A. A collection of related attributes
B. A set of entities
C. A collection of relationships of the same type
D. A set of primary keys
Answer: C
33. Which of the following is NOT a type of relationship in an ERD?
A. One-to-One
B. One-to-Many
C. Many-to-One
D. Few-to-Many
Answer: D
34. What does an ERD primarily represent?
A. Database operations
B. Database schema
C. Data flow
D. User interactions
Answer: B
35. Which of the following attributes is represented by an oval connected
to another oval?
A. Composite attribute
B. Multivalued attribute
C. Simple attribute
D. Derived attribute
Answer: A
36. What type of entity cannot exist without a related entity?
A. Strong entity
B. Weak entity
C. Recursive entity
D. Derived entity
Answer: B
