generic relation model declaration

Question

Just a quick noob question. Do I need to have content_type, object_id, and content_object every time I use GenericRelation in models? I get the concept behind generic relation but I'm confused on how to implement it.

Below is the setup.

Address - a generic content type; to be used in different models.

Company - a simple model that uses address generic content type.

Person - a simple model that uses address generic content type.

Is it essential to have these 3 attributes in all models? Thanks in advance!

Answer 1

You need this fields only inside Address model:

class Address(models.Model):
    content_type = models.ForeignKey(ContentType, on_delete=models.CASCADE)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

In models Company and Person you just specify reverse generic relation with GenericRelation:

from django.contrib.contenttypes.fields import GenericRelation
class Company(models.Model):
    addresses = GenericRelation(Address)

class Person(models.Model):
    addresses = GenericRelation(Address)

with this you can get address assosiated with person like this:

 person.addresses.all()