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WorksheetsEntity-Relationship Model Worksheet
Total questions: 15
Worksheet time: 8mins
In an ER model, what does a weak entity represent?
An entity that has a primary key
An entity that cannot be identified by its own attributes alone
An entity with many-to-many relationships
An entity with only composite attributes
Which of the following is true about the relationship in an ER diagram?
Relationships can only exist between two entities
Relationships can have attributes, and these are called relationship attributes
Relationships cannot have multiplicities
Relationships are represented as rectangles in ER diagrams
In an ER diagram, a composite attribute is:
An attribute that can be further divided into smaller subparts
An attribute that cannot be divided further
A relationship between two entities
A type of weak entity
In the ER model, which of the following can represent multivalued attributes?
A circle with a double line
A rectangle
A diamond with a double line
A double rectangle
Which of the following constraints applies to a one-to-many (1:N) relationship in an ER diagram?
The maximum cardinality of the relationship is 1 on both sides
Each entity on the "one" side can be related to multiple entities on the "many" side
The relationship has no restrictions on how many instances can exist on the "many" side
Every entity on the "many" side must be related to exactly one entity on the "one" side
Which of the following statements is true about cardinality constraints in an ER diagram?
Cardinality specifies the number of entities that can participate in a relationship
Cardinality only specifies the minimum number of relationships that can exist
Cardinality does not allow relationships to be restricted to one-to-one
Cardinality is concerned only with the number of attributes an entity can have
A university maintains a database with the following entities: Student (StudentID, Name, DateOfBirth), Course (CourseID, CourseName, Credits), Instructor (InstructorID, Name, Department), Enrollment (StudentID, CourseID, EnrollmentDate). Which type of relationship exists between Student and Course in the given database?
One-to-One
One-to-Many
Many-to-Many
Many-to-One
A company keeps a record of employees and the projects they are working on. Each employee can work on multiple projects, and each project can have multiple employees assigned to it. What is the most appropriate way to model this relationship in an ER diagram?
Use a one-to-many relationship between Employee and Project
Use a many-to-many relationship between Employee and Project
Use a one-to-one relationship between Employee and Project
Use an attribute for the Employee entity to store project data
A library has a Book entity with attributes like ISBN, Title, Author, PublicationYear, and a Member entity with attributes like MemberID, Name, MembershipDate. There is a relationship Borrows between Member and Book, which tracks which member borrows which book on a specific date. What is the best way to model this relationship?
One-to-One relationship between Member and Book
One-to-Many relationship between Member and Book
Many-to-Many relationship between Member and Book
One-to-Many relationship between Book and Member
Consider a scenario where a company has multiple departments, and each department has multiple employees. An employee can work in only one department, but a department can have many employees. Which type of relationship exists between Department and Employee?
One-to-One
One-to-Many
Many-to-Many
Many-to-One
What is the cardinality of the relationship between Supplier and Product, where each supplier can supply many products, but each product is supplied by exactly one supplier?
One-to-One (1:1)
One-to-Many (1:N)
Many-to-One (N:1)
Many-to-Many (N:M)
You are designing a system for a Hotel Reservation. You have two entities: Customer (with attributes such as CustomerID, Name, Contact) and Room (with attributes such as RoomID, RoomType, Price). The Customer can book many rooms, and each room can be booked by many customers over time. What is the correct type of relationship between Customer and Room?
One-to-One
One-to-Many
Many-to-Many
Many-to-One
A university manages the following data: Student: Contains information like StudentID, Name, and DateOfBirth. Course: Contains details like CourseID, CourseName, and Credits. Instructor: Contains information such as InstructorID, Name, and Department. Department: Contains DepartmentID and DepartmentName. How many entities are involved in this system?
2
3
4
5
In an ER diagram, the total participation of an entity in a relationship means:
Every instance of the entity must participate in the relationship
Some instances of the entity may participate in the relationship
The relationship is optional for the entity
None of the above
In a company database, Employee is related to Project through the WorksOn relationship. Every employee must work on at least one project, but some projects may not have any employees assigned to them. What kind of participation exists for the Employee and Project entities in the WorksOn relationship?
Total participation for Employee, Partial participation for Project
Partial participation for Employee, Total participation for Project
Total participation for both Employee and Project
Partial participation for both Employee and Project
