MongoDB with Django: TypeError: Model instances without primary key value are unhashable - python-3.x

Question

I'm trying to connect MongoDB with Django.
settings.py
DATABASES = {
'default': {
'ENGINE': 'djongo',
'NAME': '<name>',
'ENFORCE_SCHEMA': False,
'CLIENT': {
'host': f'mongodb+srv://{mongodb_username}:{mongodb_password}#{mongodb_cluster}/?retryWrites=true',
'uuidRepresentation': 'standard',
'waitQueueTimeoutMS': 30000
}
}
}
models.py
import uuid
from django.db import models
# Create your models here.
class ModernConnectUsers(models.Model):
user_id = models.UUIDField(primary_key=True, default=uuid.uuid4())
user_name = models.CharField(max_length=30, null=False)
The model has not been used anywhere for now.
python manage.py makemigrations && python manage.py migrate
outputs:
Migrations for 'modern_connect':
modern_connect/migrations/0003_alter_modernconnectusers_user_id.py
- Alter field user_id on modernconnectusers
Operations to perform:
Apply all migrations: admin, auth, contenttypes, modern_connect, sessions
Running migrations:
No migrations to apply.
Your models in app(s): 'modern_connect' have changes that are not yet reflected in a migration, and so won't be applied.
Run 'manage.py makemigrations' to make new migrations, and then re-run 'manage.py migrate' to apply them.
Traceback (most recent call last):
File "manage.py", line 22, in <module>
main()
File "manage.py", line 18, in main
execute_from_command_line(sys.argv)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 446, in execute_from_command_line
utility.execute()
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 440, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/base.py", line 414, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/base.py", line 460, in execute
output = self.handle(*args, **options)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/base.py", line 98, in wrapped
res = handle_func(*args, **kwargs)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/commands/migrate.py", line 317, in handle
emit_post_migrate_signal(
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/core/management/sql.py", line 52, in emit_post_migrate_signal
models.signals.post_migrate.send(
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/dispatch/dispatcher.py", line 176, in send
return [
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/dispatch/dispatcher.py", line 177, in <listcomp>
(receiver, receiver(signal=self, sender=sender, **named))
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/contrib/auth/management/__init__.py", line 83, in create_permissions
ctypes.add(ctype)
File "/home/sarvesh/PycharmProjects/modernConnect/venv/lib/python3.8/site-packages/django/db/models/base.py", line 597, in __hash__
raise TypeError("Model instances without primary key value are unhashable")
TypeError: Model instances without primary key value are unhashable
The only collection I'm currently using has a Primary Key, but for some reason - The program is falling for self.pk == None in Base.py which is raising this error. Solutions under other questions didn't help, so starting another question.

Answer 1

In your models.py, try importing the models from djongo.
from djongo import models
And for primary key I use
class User(models.Model):
_id = models.ObjectIdField()
But you can play around with uuid() and see if it works or not.