Django prefetch_related with m2m through relationship

Question

I have the following models

class Film(models.Model):
    crew = models.ManyToManyField(\'Person\', through=\'Role\', blank=True)

class Role(models.Model):
             


        

Answer 1

You can construct your queryset like this:

from django.db.models import Prefetch

def get_queryset(self):
    return super(FilmDetail, self).get_queryset().prefetch_related(
        Prefetch(
            'crew',
            queryset=Role.objects.select_related(
                'person',
                'person_role',
            ),
        ),
    )

Only Film->Role is a backwards relation loadable with prefetch_related. Role->RoleType and Role->Person are forwards relations that you load with select_related.