Models which link to Groups (by ForeignKey)

[Benjamin SOULAS]

Hello everyone,

I want to implement a model which make references to 2 groups, to do this, I thought I had to defined, in the model which links the 2 groups, a foreign key for each Group like this:

from django.contrib.auth.models import Group
from django.db import models


class GroupLinker(models.Model):
    EMSGroup = models.ForeignKey(Group, on_delete=models.CASCADE)
    LDAPGroup = models.ForeignKey(Group, on_delete=models.CASCADE)

But I got that error: 

ERRORS:

api.GroupLinker.EMSGroup: (fields.E304) Reverse accessor for 'GroupLinker.EMSGroup' clashes with reverse accessor for 'GroupLinker.LDAPGroup'.

        HINT: Add or change a related_name argument to the definition for 'GroupLinker.EMSGroup' or 'GroupLinker.LDAPGroup'.

api.GroupLinker.LDAPGroup: (fields.E304) Reverse accessor for 'GroupLinker.LDAPGroup' clashes with reverse accessor for 'GroupLinker.EMSGroup'.

        HINT: Add or change a related_name argument to the definition for 'GroupLinker.LDAPGroup' or 'GroupLinker.EMSGroup'.

I don't understand why I should add a related name, because my future table will just link my 2 groups right? Where am I wrong?

Kind regards,

Benjamin.

[Jason]

https://stackoverflow.com/questions/2642613/what-is-related-name-used-for-in-django

As you can see there, its for the relation from Group to GroupLinker.  That relation name is the same for both fields, so you need to specify something unique.

[Benjamin SOULAS]

Ow, ok, I got it, thx a lot

But in order to create this object (retrieve my groups from the ORM), should I implement something specific? Because for my request, I just want to specify the group names and then, in my app, retrieve those, create my link between the groups...

I thought I had to retrieve the groups in my GroupLinkerSerializer and, then, create my instance, but to create it (correct me if I am wrong), I should retrieve Group objects and instantiate my GroupLinkerSerializer AND create it (with .create method) right?

I am not comfortable with the regular process, my API don't use a lot the ORM (only for User, Groups and Permissions).

Kind regards,

Benjamin