1. Which of the following best describes an entity in the Entity-Relationship (ER) Model?
A) An attribute of a relationship
B) A real-world object or concept represented in the database
C) A foreign key used to join two tables
D) A primary key in the database
2. What is an entity set in the ER model?
A) A set of all attributes
B) A set of similar entities in the database
C) A relation in the database
D) A primary key of a table
Correct answer
B) A set of similar entities in the database
3. Which of the following defines a weak entity?
*
1/1
A) An entity that can be uniquely identified by its attributes alone
B) An entity that depends on another entity for its existence
C) An entity that contains no attributes
D) An entity that has no relationships
4. What is a primary key in an ER diagram?
A) A unique identifier for a set of entities
B) A constraint that limits the number of entities
C) A composite attribute of an entity
D) An attribute that can have multiple values
5. What is a relationship type in an ER diagram?
A) An attribute of an entity
B) A way of defining how entities are related to each other
C) A primary key for each entity
D) An attribute that acts as a foreign key
6. How are weak entities represented in ER diagrams?
A) By a rectangle with a single line border
B) By a rectangle with a double line border
C) By a diamond shape with a double border
D) By a dashed line
7. What is the role of an attribute in an ER model?
A) It defines the constraints between two entities
B) It describes the characteristics of an entity
C) It links two relations in the relational model
D) It is used to describe relationships between entities
8. What is a composite attribute in ER diagrams?
A) An attribute with no unique values
B) An attribute that can be divided into smaller attributes
C) An attribute that acts as a key
D) An attribute that has only one value
9. Which of the following is a correct example of a derived attribute?
A) Name of a student
B) Age calculated from the date of birth
C) Address of a person
D) Social security number
10. In an ER diagram, how are relationships depicted?
A) As rectangles
B) As ellipses
C) As diamonds
D) As triangles
11. Which of the following is true about the cardinality of a relationship?
A) It represents the degree of participation of entities in a relationship
B) It is the number of relationships in the database
C) It defines the type of attribute
D) It is a set of all possible attributes
12. What is a multivalued attribute in the ER model?
A) An attribute that can take only one value
B) An attribute that can have multiple values for an entity
C) An attribute that acts as a foreign key
D) An attribute with unique constraints
13. What is the main purpose of an ER diagram in database design?
A) To define the structure of tables
B) To model the data and its relationships visually
C) To enforce database constraints
D) To normalize the database
14. How are composite keys represented in an ER diagram?
A) By underlining all the attributes that form the key
B) By using a diamond shape
C) By using a dashed line
D) By double underlining the attributes
15. What does the "role" mean in the context of a relationship in the ER model?
A) The part played by an entity in a relationship
B) A unique identifier for the entity
C) The primary key of the relation
D) The participation level of a weak entity
16. What are structural constraints in ER diagrams?
A) Rules governing the structure of tables
B) Constraints defining how many instances of an entity can participate in a relationship
C) A primary key rule for relationships
D) A set of derived attributes
17. How are many-to-many relationships implemented in a relational database?
A) By creating a direct foreign key between the two entities
B) By creating a third table to link the two entities
C) By using a composite primary key in one of the entities
D) By using a weak entity
18. Which of the following is NOT an advantage of using an ER diagram for data
modeling?
A) Provides a visual representation of relationships
B) Helps in normalizing data
C) Defines attributes and their relationships
D) Enforces all business rules
19. What is a "total participation" constraint in an ER model?
A) When some instances of an entity must participate in a relationship
B) When all instances of an entity must participate in a relationship
C) When an entity has a composite key
D) When an entity has no relationships
20. What is the main difference between a weak entity and a regular (strong) entity?
A) A weak entity is not uniquely identified by its own attributes, while a regular entity is
B) A weak entity has no relationships, while a regular entity has many relationships
C) A weak entity is a foreign key, while a regular entity is a primary key
D) A weak entity does not participate in any relationship
21. In an ER diagram, what is the significance of double lines in a relationship?
A) It represents a weak relationship.
B) It indicates total participation of an entity in a relationship.
C) It signifies a derived relationship.
D) It shows a recursive relationship.
22. What is the significance of a discriminator attribute in a weak entity?
A) It helps in identifying the relationship between two weak entities.
B) It uniquely identifies weak entities related to the same strong entity.
C) It is used as a foreign key to another weak entity.
D) It acts as a composite key for weak entities.
23. In a relational database schema, how is a one-to-many relationship implemented?
A) By adding a composite key in both entities
B) By adding a foreign key to the "one" side of the relationship
C) By adding a foreign key to the "many" side of the relationship
D) By creating a separate table for the relationship
24. What is a naming convention in database design?
A) A set of rules for naming tables and attributes consistently
B) A constraint applied to primary keys
C) A foreign key relationship
D) A rule for defining composite attributes
25. What are design issues typically addressed during data modeling?
A) Defining foreign key constraints
B) Ensuring consistent naming conventions, avoiding redundancy, and ensuring data integrity
C) Creating indexes for better performance
D) Identifying derived attributes
