ER Diagram for an Online Course Platform (Visio Example, Crow's Foot)
Students, courses, enrolments and lessons. Draw the online course platform ER diagram in Visio with crow's foot notation, fix the many-to-many between student and course with an enrolment entity, and put each foreign key on the right side.
Step by step
- Online course ERD. An online course platform. Students, courses and lessons. It's a common ER diagram task, and it hides a many to many. Let's draw it in Visio with crow's foot notation.
- Crow's Foot stencil. I'm using the Crow's Foot Database Notation stencil.
- Student. Start with student. Student ID is the primary key, then a name and an email.
- Course. Then course, on the far side. Course ID, a title and a price.
- Enrolment. A student takes many courses, and a course has many students. That's many to many. So enrolment goes in the middle, holding both keys. Connect student to enrolment. One student has zero or many enrolments. And course to enrolment. One course has zero or many. A brand new course has none yet.
- Lesson. Now the lessons, under course. Lesson ID, the course ID it belongs to, and a title. Connect course down to lesson. One course has one or many lessons. A course with no lessons can't be published.
- Where data goes. Enrolment is where the useful data goes later. The date joined, the progress, the grade. All of it is about one student on one course.
- Done. Click away to see the finished model.
- The rule. So, student and course are many to many, fixed by enrolment. Course to lesson is one to many, and the foreign key sits in lesson. Four entities, three relationships.
