连接三个表的表代码

Question

What would be the most elegant and maintainable way to write join table for 3 other tables?

Lets say I have three tables: School, Student, Teacher, all with primary keys (IDs).

Student can attend many schools, have many teachers. Teachers can teach in many schools. Teacher can teach same student in different school (or not).

I seen many articles with Many-to-Many relationships between two tables, but cannot find a right way to deal with three tables,,

Any suggestions welcome.

Answer 1

Firstly -in my opinion- you need to add something like the concept of Course . It is the relationship that tells you which Student s some Teacher teaches in some specific School .

I introduce it because I guess that not all Teacher s teaching in some School teach all Student s attending to that School .

• Course is kept on one School . School can have many Course s. (relationship)

• Course has many Student s. Studend attends to many Course s. (relationship)

• Teacher teach many Course s. Course has one teacher. (relationship)

In this set there is one ManyToMany relationship namely Student - Course . Course has ManyToOne relationships to Teacher & School .

Answer 2

I would go with using an ORM to help you with these kinds of relationships. I think your relationship is many-to-many-through relationship.

Here's an article showing a possible match to what you want.

Describing Relationships: Django's ManyToMany Through