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HINT: Update the relation to point at 'settings.AUTH_USER_MODEL'

Hello I had to rewrite my user model for add some filed, I used AbstractUser
My models:
It's on blog app:
class Article(models.Model):
author = models.ForeignKey(User , null=True, on_delete=models.SET_NULL , related_name='articles' , verbose_name='نویسنده')...
it's on account app:
from django.db import models
from django.utils import timezone
from django.contrib.auth.models import AbstractUser
class User(AbstractUser):
is_authour = models.BooleanField(default=False, verbose_name="وضعیت نویسندگی")
special_user = models.DateTimeField(default=timezone.now, verbose_name="کاربر ویژه تا")
def is_special_user(self):
if self.special_user > timezone.now():
return True
else:
return False
is_special_user.boolean = True
is_special_user.short_description = "وضغیت کاربر ویژه"
I imported my User view in this way:
from account.models import User
And I added this to my setting:
AUTH_USER_MODEL = 'account.User'
when I migrate I get this error:
blog.Article.author: (fields.E301) Field defines a relation with the
model 'auth.User', which has been swapped out.
HINT: Update the relation to point at 'settings.AUTH_USER_MODEL'.
I searched my error but I can't find my solution

The current User passed to the ForeignKey points to the auth.User right now, not your custom User.
As the HINT itself suggests, use settings.AUTH_USER_MODEL instead of User in your author field in Article model.
class Article(models.Model):
author = models.ForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete=models.SET_NULL, related_name='articles', verbose_name='نویسنده')...

Link to django docs: Using a custom user model
Did you register the model in the app's admin.py?
Furthermore, changing the user model mid-project...this can be a hassle, look here: Changing to a custom user model mid-project

I think you are importing User model from django auth app.
Change the author field in the Article model as follows:
class Article(models.Model):
author = models.ForeignKey('account.User', null=True, on_delete=models.SET_NULL, related_name='articles', verbose_name='نویسنده')
...

Default user in django (sentinel value)

I have a model:
class NotificationSettings(models.Model):
android_device = models.ForeignKey(
'users.AndroidDevice',
default=None,
null=True,
blank=True,
on_delete=models.SET_NULL
)
user = models.ForeignKey(settings.AUTH_USER_MODEL, blank=True, null=True)
...
class Meta:
unique_together = ("user", "android_device")
My problem is that I have unique_together on fields that are nullable. I learned that in PostgreSQL (and generally in the SQL standard) NULL != NULL, so I can end up with, for example, two NotificationSettings objects that have the same device_id and user is NULL in both cases.
I thought that using NotificationSettings.objects.get_or_create() everywhere I create these objects would suffice but I guess there is a race condition when two request are hitting the endpoint in almost the same time, and I end up with duplicates anyway.
This is why I wanted to make this constraint on the PostgreSQL level and was thinking about changing the user field to not being nullable and having default user instead.
But I feel like creating default user might have some kind of security consequences.
So my question is: Is this a good practice (or practice at all) to create such a sentinel/default user object? Are there any caveats/security risks?

I've just stumbled across this in django docs:
from django.conf import settings
from django.contrib.auth import get_user_model
from django.db import models
def get_sentinel_user():
return get_user_model().objects.get_or_create(username='deleted')[0]
class MyModel(models.Model):
user = models.ForeignKey(
settings.AUTH_USER_MODEL,
on_delete=models.SET(get_sentinel_user),
)
So I guess it's OK to have a sentinel users in a DB.

Users as foreign key in Django

I have the below in my models.py file:
class Film(models.Model):
title = models.CharField(max_length=200)
director = models.CharField(max_length=200)
description = models.CharField(max_length=200)
pub_date = models.DateField('date published')
class Comment(models.Model):
film = models.ForeignKey(Film, on_delete=models.CASCADE)
body = models.CharField(max_length=200)
When I logged into Django admin I added some films, and then added some comments, selecting which film object the comment related to. I then created a couple of users via the admin panel also.
I would like my relationships to be:
Film can have many comments / Comments belong to film
User can have many comments / Comments belong to user
I think, like with comments and films, I just need to define user as a foreign key to comment. I am struggling to do this. I am working through the Django tutorials but I can't see the tutorials covering how I can link other tables to the user.
I thought I would be able to do something like this:
user = models.ForeignKey(User, on_delete=models.CASCADE)
While importing User like this:
from django.contrib.auth.models import User
The result at the moment is if I keep user = models.ForeignKey(User, on_delete=models.CASCADE) I get err_connection_refused

Maybe have you changed your default user model in the settings?
Instead of using User directly with the the Foreign key, you should use user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE) in your Comment Model, as follow
class Comment(models.Model):
film = models.ForeignKey(Film, on_delete=models.CASCADE)
body = models.CharField(max_length=200)
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
You need to apply migrations to be able to add user to Comment,
python manage.py makemigrations
python manage.py migrate
if at the moment that you are applying migrations, shell shows a message telling You are trying to add a non-nullable field 'user' to comment without a default
You have 2 Options
Skip migrations and add a default value to the field in the models or set the attribute as nullable, whatever else that you need
ie
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, null=True, blank=True)
and apply migrations again
Or select a default value to the new field, should be an id of an existing user in databse
This is because django should populate existing records in database, if exist

Use "settings.AUTH_USER_MODEL".
So, import "settings" from "django.conf", then use "settings.AUTH_USER_MODEL" as shown below:
from django.db import models
from django.conf import settings # Here
class Comment(models.Model):
film = models.ForeignKey(Film, on_delete=models.CASCADE)
body = models.CharField(max_length=200)
# Here
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)

foreignkey (user) in models

I read the docs and this post... Django - Foreign Key to User model
I followed what it said and I still cannot get it to work. When I try to run the migrations I get this error in the traceback...
django.db.utils.ProgrammingError: column "author_id" cannot be cast automatically to type integer
HINT: You might need to specify "USING author_id::integer".
I just don't know how to go about fixing that error.
from django.db import models
from django.contrib.auth.models import User
# Create your models here.
class BlogCategory(models.Model):
'''model for categories'''
title = models.CharField(max_length=30)
description = models.CharField(max_length=100)
class BlogPost(models.Model):
'''a model for a blog post'''
author = models.ForeignKey(User)
date = models.DateField()
title = models.CharField(max_length=100)
post = models.TextField()

Don't use the User model directly.
From the documentation
Instead of referring to User directly, you should reference the user
model using django.contrib.auth.get_user_model()
When you define a foreign key or many-to-many relations to the user model, you should specify the custom model using the AUTH_USER_MODEL setting.
Example:
from django.conf import settings
from django.db import models
class Article(models.Model):
author = models.ForeignKey(
settings.AUTH_USER_MODEL,
on_delete=models.CASCADE,
)

If you created a custom User model, you would use setting.AUTH_USER_MODEL, if not you can go ahead an use User model
Referencing Django User model

the column "author_id" doesn't exist, looks like is the same problem from here : Django suffix ForeignKey field with _id , so to avoid this traceback you may use :
author = models.ForeignKey(User, db_column="user")

I do not know the "settings.AUTH_USER_MODEL" approach but a well-known approach and commonly used is the "Auth.User" model. Something like this on your end.
from django.contrib.auth.models import User
class BlogPost(models.Model):
'''a model for a blog post'''
author = models.ForeignKey(User)
date = models.DateField()
title = models.CharField(max_length=100)
post = models.TextField()

Creating many to many relation with AUTH_USER_MODEL in django via intermediary model

I am trying to create the following models. There is a ManyToMany relation from Entry to AUTH_USER_MODEL via the EntryLike intermediate model.
class BaseType(models.Model):
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
creation_time = models.DateTimeField(auto_now_add=True)
last_update_time = models.DateTimeField(auto_now=True)
class Meta:
abstract = True
class Title(BaseType):
text = models.CharField(max_length=100)
description = models.TextField()
class EntryLike(BaseType):
entry = models.ForeignKey(Entry)
user = models.ForeignKey(settings.AUTH_USER_MODEL)
class Entry(BaseType):
title = models.ForeignKey(Title, on_delete=models.PROTECT)
text = models.TextField()
user = models.ForeignKey(settings.AUTH_USER_MODEL)
liked_by_users = models.ManyToManyField(settings.AUTH_USER_MODEL, through='EntryLike', through_fields=('entry', 'user'))
Running migrations on the above model scheme throws the error: AttributeError:'str' object has no attribute 'meta'.
Any help in resolving this error would be highly appreciated. Am new to Django & Python, but not to Web Development.

The issue is that settings.AUTH_USER_MODEL is almost certainly not a model instance. It's probably a string that constrains the choices another model can make - settings would be a strange place to leave a model definition.
To do a MTM between the user model and your field above you need need to do:
from django.contrib.auth.models import User
class Entry(BaseType):
title = models.ForeignKey(Title, on_delete=models.PROTECT)
text = models.TextField()
user = models.ForeignKey(User)
def __str__(self):
return self.title
I've added the str function so that it gives a more sensible return when you're manipulating it in admin/shell.
I'd also question whether you need the second set of fields (removed here), as you can use select related between the Entry and EntryLike join table, without any duplication of the fields - you can probably go that way, it's just a bit unnecessary.
Lastly, I'd note that the way I'm using it above just uses the default User object that comes with Django - you may wish to customise it. or extend the base class as you've done here with your own models' base class.
(All of this is predicated on AUTH_USER_MODEL not being a model instance - if it is, can you post the model definition from settings.py? )