ER Diagram Practice Questions

Question 1: University Course Management System

Domain: Education

Scenario:
A university wants to design a system to manage courses, instructors, and student enrollments.

Requirements:

• The university offers multiple courses. Each course has a unique course ID, title, number of credits, and department.

• Instructors teach one or more courses. Each instructor has a unique ID, name, email, and office number.

• Students can enroll in multiple courses. Each student has a unique ID, name, email, and date of birth.

• For every enrollment, the system should record the enrollment date and final grade.

• Each course is taught by one instructor only.

• A student can enroll in a course only once per semester.

Task:
Draw the ER diagram showing entities like Student, Course, Instructor, Enrollment, and their relationships with appropriate attributes and cardinalities.

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Question 2: Online Retail Store System

Domain: E-commerce

Scenario:
An online retail store wants to manage its customers, orders, and products.

Requirements:

• Customers have a unique ID, name, email, phone number, and shipping address.

• Products have a unique product ID, name, description, price, and quantity in stock.

• Customers can place multiple orders. Each order has a unique order ID, order date, and status.

• An order can contain multiple products, and a product can appear in multiple orders (many-to-many).

• The system should track the quantity of each product ordered and its price at the time of order.

• Each order is placed by one customer only.

Task:
Design an ER diagram showing entities such as Customer, Order, Product, and OrderDetails (associative entity), with appropriate attributes and relationships.

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Question 3: Hospital Patient Management System

Domain: Healthcare

Scenario:
A hospital wants to develop a database to manage patients, doctors, and appointments.

Requirements:

• Patients have a unique ID, name, gender, date of birth, and address.

• Doctors have a unique ID, name, specialization, and contact number.

• Each appointment has a unique ID, appointment date, time, and status (e.g., scheduled, completed, canceled).

• A patient can have multiple appointments with one or more doctors.

• A doctor can see multiple patients through appointments.

• The system should record which doctor sees which patient and the details of the appointment.

Task:
Create an ER diagram with entities like Patient, Doctor, and Appointment, including attributes and relationships with cardinalities.

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Question 4: Library Management System

Domain: Library Services

Scenario:
A library is setting up a database system to manage books, members, and borrowing records.

Requirements:

• Books have a unique ISBN, title, author, publisher, and the number of copies.

• Members have a unique ID, name, membership date, email, and phone number.

• Each member can borrow multiple books, and a book can be borrowed by multiple members (many-to-many).

• For every borrowing instance, record the issue date and return date.

• A member cannot borrow the same book more than once at the same time (until it is returned).

• The library may hold multiple copies of the same book.

Task:
Design an ER diagram that captures entities like Book, Member, Borrow, and their relationships, including all necessary attributes and cardinalities.