Question

What is the difference between ManytoManyField Relationship and a Foreign Key?

Answer 1

Strange question. A many to many relationship would imply a table that holds the relationships, for example PRIMARY_KEY = 1, FOREIGN_KEY_1 = 23; FOREIGN_KEY_2 = 42 would mean that the record with ID 23 is connected to the record with id 42.

Answer 2

An example of a many to many relationship would be "teachers can have many students, students can have many teachers." You would represent this by having separate tables for students and teachers, and a table like "courses" that uses foreign keys to link students to teachers.

A foreign key is used to eliminate redundancy in a database by taking the primary key of one table and using it in another table. For example, in a table "courses" you may need to include students and teachers in a particular course. To do this, you will need to have a foreign key for TEACHER_ID and a foreign key for STUDENT_ID. These same IDs would be primary keys in separate tables you would have for teachers and students.

Answer 3

Many to many relationships are typically frowned upon in database design. The suggested trick is to create a junction table where the many to many relationship exists in your structure.