Free online ER diagram maker
Effortlessly make ER diagrams online for free with our rich templates and symbols.
How to create an ER diagram for a real database system
An ER diagram models a database through entities, attributes, keys, and relationships. EdrawMax helps turn a database concept into a clear visual model before implementation.
Hospital management system example
Start with Patient, Doctor, Appointment, Department, Room, Prescription, and Bill. Add keys and attributes, then define relationships—for example, a patient can have many appointments, while each appointment links a patient with a doctor.
College management system example
Common entities include Student, Course, Instructor, Department, Enrollment, and Classroom. Enrollment can resolve the many-to-many relationship between students and courses.
ER diagram checklist
- Identify core entities and keys.
- Define one-to-one, one-to-many, and many-to-many cardinalities.
- Resolve many-to-many relationships with an associative entity where appropriate.
- Review the model against actual business rules.
For grouping ideas rather than database relationships, use a cluster diagram or mind map instead.
How to make an ER diagram in 3 Simple Steps
(AI & Web)
Free ER diagrams templates from EdrawMax