Q. In an ER diagram, how is a multi-valued attribute represented?
A.As a rectangle
B.As an oval
C.As a double oval
D.As a diamond
Solution
A multi-valued attribute is represented as a double oval in an ER diagram.
Correct Answer: C — As a double oval
Q. In an ER model, what does a circle represent?
A.An entity
B.An attribute
C.A relationship
D.A weak entity
Solution
A circle in an ER model represents an attribute of an entity.
Correct Answer: B — An attribute
Q. In an ER model, what is an attribute?
A.A relationship between entities
B.A property or characteristic of an entity
C.A unique identifier for an entity
D.A type of database operation
Solution
An attribute is a property or characteristic that describes an entity in an ER model.
Correct Answer: B — A property or characteristic of an entity
Q. What does a primary key do in an ER model?
A.Links two entities
B.Identifies a unique record
C.Defines a relationship type
D.Stores multiple values
Solution
A primary key uniquely identifies a record in a database table.
Correct Answer: B — Identifies a unique record
Q. What does a primary key in an ER model signify?
A.A unique identifier for an entity
B.A foreign key reference
C.An attribute that can be null
D.A relationship type
Solution
A primary key signifies a unique identifier for an entity in an ER model.
Correct Answer: A — A unique identifier for an entity
Q. What does an entity represent in an ER model?
A.A relationship between two tables
B.A real-world object or concept
C.A specific attribute of a table
D.A constraint on data
Solution
An entity represents a real-world object or concept in an ER model.
Correct Answer: B — A real-world object or concept
Q. What is a primary key in the context of an ER model?
A.A key that allows for data redundancy
B.A unique identifier for each entity instance
C.A foreign key that links to another table
D.A type of relationship between entities
Solution
A primary key is a unique identifier for each instance of an entity, ensuring that no two instances are the same.
Correct Answer: B — A unique identifier for each entity instance
Q. What is the main advantage of using an ER model?
A.It is easy to implement in SQL
B.It provides a clear visual representation of data
C.It eliminates the need for normalization
D.It allows for complex queries
Solution
The main advantage of using an ER model is that it provides a clear visual representation of data and relationships.
Correct Answer: B — It provides a clear visual representation of data
Q. What is the main purpose of an ER model?
A.To define SQL queries
B.To visualize database structure
C.To manage transactions
D.To optimize indexing
Solution
The main purpose of an ER model is to visualize the structure of a database, including entities, attributes, and relationships.
Correct Answer: B — To visualize database structure
Q. What is the purpose of an associative entity in an ER model?
A.To represent a many-to-many relationship
B.To store attributes of a relationship
C.To simplify complex relationships
D.All of the above
Solution
An associative entity is used to represent a many-to-many relationship and can store attributes of that relationship.
Correct Answer: D — All of the above
Q. What is the purpose of normalization in database design?
A.To increase redundancy
B.To eliminate data anomalies
C.To simplify the ER diagram
D.To enhance query performance
Solution
Normalization is used to eliminate data anomalies and reduce redundancy in database design.
Correct Answer: B — To eliminate data anomalies
Q. What is the role of attributes in an ER model?
A.To define relationships
B.To provide additional information about entities
C.To serve as primary keys
D.To represent constraints
Solution
Attributes provide additional information about entities in an ER model.
Correct Answer: B — To provide additional information about entities
Q. Which of the following is a characteristic of a weak entity?
A.It can exist independently of other entities
B.It has a primary key of its own
C.It relies on a strong entity for its identification
D.It cannot have attributes
Solution
A weak entity relies on a strong entity for its identification and does not have a primary key of its own.
Correct Answer: C — It relies on a strong entity for its identification
Q. Which of the following is an example of a weak entity?
A.A customer with a unique ID
B.An order that depends on a customer
C.A product with a SKU
D.A department with a manager
Solution
An order that depends on a customer is an example of a weak entity, as it cannot exist without the customer.
Correct Answer: B — An order that depends on a customer
Q. Which of the following is NOT a type of relationship in an ER model?
A.One-to-One
B.One-to-Many
C.Many-to-Many
D.Many-to-One
Solution
All listed options are types of relationships in an ER model; however, 'Many-to-One' is typically described as 'One-to-Many' from the other entity's perspective.
