[Django]-Django : How can I find a list of models that the ORM knows?

Simple solution:

import django.apps
django.apps.apps.get_models()

By default apps.get_models() don’t include

• auto-created models for many-to-many relations without
  an explicit intermediate table
• models that have been swapped out.

If you want to include these as well,

django.apps.apps.get_models(include_auto_created=True, include_swapped=True)

Prior to Django 1.7, instead use:

from django.db import models
models.get_models(include_auto_created=True)

The include_auto_created parameter ensures that through tables implicitly created by ManyToManyFields will be retrieved as well.

If you want a dictionary with all models you can use:

from django.apps import apps

models = {
    model.__name__: model for model in apps.get_models()
}

List models using http://docs.djangoproject.com/en/dev/ref/contrib/contenttypes/

from django.contrib.contenttypes.models import ContentType

for ct in ContentType.objects.all():
    m = ct.model_class()
    print "%s.%s\t%d" % (m.__module__, m.__name__, m._default_manager.count())

If you want to play, and not use the good solution, you can play a bit with python introspection:

import settings
from django.db import models

for app in settings.INSTALLED_APPS:
  models_name = app + ".models"
  try:
    models_module = __import__(models_name, fromlist=["models"])
    attributes = dir(models_module)
    for attr in attributes:
      try:
        attrib = models_module.__getattribute__(attr)
        if issubclass(attrib, models.Model) and attrib.__module__== models_name:
          print "%s.%s" % (models_name, attr)
      except TypeError, e:
        pass
  except ImportError, e:
    pass

Note: this is quite a rough piece of code; it will assume that all models are defined in “models.py” and that they inherit from django.db.models.Model.

If you use the contenttypes app, then it is straightforward: http://docs.djangoproject.com/en/dev/ref/contrib/contenttypes/

If you register your models with the admin app, you can see all the attributes of these classes in the admin documentation.

Here’s a simple way to find and delete any permissions that exist in the database but don’t exist in the ORM model definitions:

from django.apps import apps
from django.contrib.auth.management import _get_all_permissions
from django.contrib.auth.models import Permission
from django.core.management.base import BaseCommand


class Command(BaseCommand):
    def handle(self, *args, **options):
        builtins = []
        for klass in apps.get_models():
            for perm in _get_all_permissions(klass._meta):
                builtins.append(perm[0])
        builtins = set(builtins)

        permissions = set(Permission.objects.all().values_list('codename', flat=True))
        to_remove = permissions - builtins
        res = Permission.objects.filter(codename__in=to_remove).delete()
        self.stdout.write('Deleted records: ' + str(res))