Many to many reverse relationship Django

Question

I am trying to write a simple messages system.

Basically I have a User table and a Message table.

class User(models.Model):
   user = models.OneToOneField(User)# inherit djangos default user properties
   messages = models.ManyToManyField(Message)

.

class Message(models.Model):
   date = models.DateField()
   text = models.CharField(max_length=255)
   user = models.ManyToManyField(User)

I want to be able to add as many users to as many messages as possible.

I want to be able to say messages.users and users.messages.

What is the best way to accomplish this?

Answer 1

You shouldn't define the relationship on both sides. Pick one - probably Messages - and define it there. Django automatically provides the reverse relationship.

Also, you don't need a separate User class, especially if the M2M field is on messages itself. So, you can just do this:

class Message(models.Model):
   date = models.DateField()
   text = models.CharField(max_length=255)
   users = models.ManyToManyField('auth.User')

And now you can access the messages for a user with my_user.message_set.all(), and the users for a message with my_messages.users.all().