Let’s give a brief introduction to how to draw database entity diagrams and E-R diagrams.
The E-R diagram makes associations based on the relationships between entities. The easiest way to distinguish associations is to look at foreign keys or the connections between entities to build a complete E-R diagram.
Drawing tool: Visio
If there is anything wrong, please correct me!
Take the course selection system as an example. The system includes four entities: administrator (admin), students (students), courses (classes), and course selection records (xuanke). The database table design is as follows.
The foreign key association design associates the course selection record with the student ID and course ID.
Then use the visio drawing tool to draw. You can use Chen's database representation in shapes to quickly draw entities, associations, and connections.
If it is an entity and its attribute diagram drawing, it can be completed by directly connecting attributes and entities.