django two foreign key for same model - django

Question

my model
class BaseModel(models.Model):
CreatedDate = models.DateTimeField(auto_now_add=True, verbose_name="Oluşturulma Tarihi")
ModifiedDate = models.DateTimeField(auto_now=True, verbose_name="Son Güncellenme tarihi")
Isdeleted = models.BooleanField(verbose_name="Silindi", default=False)
class Case(BaseModel):
CaseNumber = models.CharField(max_length=14)
Customer = models.ForeignKey(Customer)
Title = models.ForeignKey(CaseTitle)
CaseCategory = models.ForeignKey(CaseCategory, verbose_name="Kategori")
Priority = models.ForeignKey(CasePriority)
Status = models.ForeignKey(CaseStatus)
Detail = models.TextField()
Group = models.ForeignKey(Group)
User = models.ForeignKey(User,related_name='User' )
AssignedUser = models.ForeignKey(User,related_name='AssignedUser')
CloseDetail = models.TextField blank=True)
i just want to give 2 foreign key this my model but error is
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/django/db/models/fields/related.py", line 796, in __init__
to._meta.model_name AttributeError: 'ForeignKey' object has no attribute '_meta'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "manage.py", line 22, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
utility.execute()
File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 338, in execute
django.setup()
File "/usr/local/lib/python3.6/site-packages/django/__init__.py", line 27, in setup
apps.populate(settings.INSTALLED_APPS)
File "/usr/local/lib/python3.6/site-packages/django/apps/registry.py", line 108, in populate
app_config.import_models()
File "/usr/local/lib/python3.6/site-packages/django/apps/config.py", line 202, in import_models
self.models_module = import_module(models_module_name)
File "/usr/local/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 678, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/code/Case/models.py", line 91, in <module>
class Case(BaseModel):
File "/code/Case/models.py", line 101, in Case
AssignedUser = models.ForeignKey(User,related_name='AssignedUser')
File "/usr/local/lib/python3.6/site-packages/django/db/models/fields/related.py", line 802, in __init__
RECURSIVE_RELATIONSHIP_CONSTANT, AssertionError: ForeignKey(<django.db.models.fields.related.ForeignKey>) is invalid.
First parameter to ForeignKey must be either a model, a model name, or the string 'self'

Answer 1

You're redefining User The relevant section of Django code this is bombing on is an isinstance(to, str) which means User is not a model but it's also not a string (it's a ForeignKey).
If you're using Django's User model or a customized variant the correct way to obtain a reference independently is to use django.contrib.auth.get_user_model(). e.g.:
from django.contrib.auth import get_user_model
User = get_user_model()
class MyModel(models.Model):
user = models.ForeignKey(User)
In Python it's convention to lowercase names unless they are classes.

Answer 2

Does it work if you only implement one relationship to the model User? The error message:
First parameter to ForeignKey must be either a model, a model name, or the string 'self'
lets me assume, that you're not passing the actual class of the User model. How do you obtain it?
Also, from looking at the fields of BaseModel I suppose, it could be an abstract base model:
class BaseModel(models.Model):
class Meta:
abstract = True
CreatedDate = models.DateTimeField(auto_now_add=True, verbose_name="Oluşturulma Tarihi")
...
See here for more information: https://godjango.com/blog/django-abstract-base-class-model-inheritance/

Answer 3

You should be following the python conventions on how to use uppercase, lowercase, otherwise the interpreter is going to refer to wrong variables:
Classes are the only things that should be camel-case (class User, class CaseTitle).
Your class properties (instance variables) should be lowercase with underscores: case_number, user, assigned_user, etc...
When you write User = ForeignKey(User) you're actually redefining the User variable, so in the next line AssignedUser = ForeignKey(User), User isn't the User model class anymore. If I write it out, I get:
AssignedUser = models.ForeignKey( # User
models.ForeignKey( # User
models.ForeignKey( # User etc...
...

Answer 4

Change the field name User to anything you want. It conflicts that's why you get the error.
class Case(BaseModel):
....
user = models.ForeignKey(User,related_name='user' )
assigned_user = models.ForeignKey(User,related_name='assigned_user')