When trying to create an account number, I get an IntegrityError: FOREIGN KEY constraint failed - django-models

Question

I want that when creating an account number, the owner of the account be the current logged-in user.
I have read about foreign key constraints but do not know what constraint the CustomUser class is having to conflict the creation of an account number.
I have tried setting on_delete to CASCADE but still it throws the IntegrityError
Please help. Thanks.
My models.py
class CustomUser(TrackingModel, AbstractUser, PermissionsMixin):
GENDER = (
("F", "Female"),
("M", "Male"),
("NS", "Not Specified"),
)
id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
phone = models.CharField(max_length=20)
gender = models.CharField(max_length=6, choices=GENDER)
USERNAME_FIELD = "username"
REQUIRED_FIELDS = [
"phone",
]
#property
def token(self):
token = jwt.encode(
{
"username": self.username,
"email": self.email,
"exp": datetime.utcnow() + timedelta(hours=24),
},
settings.SECRET_KEY,
algorithm="HS256",
)
return token
def __str__(self):
return self.username
class Accountnumber(TrackingModel):
TYPE = (
("momo", "MTN Mobile Money"),
("om", "Orange Money"),
("visa", "Visa"),
("paypal", "Paypal"),
)
number = models.AutoField(primary_key=True, editable=False, default=9999)
type = models.CharField(
max_length=10,
choices=TYPE,
null=True,
default="momo",
)
customuser = models.ForeignKey(
CustomUser,
related_name="acc_no_user",
on_delete=models.CASCADE,
)
cdate = models.DateTimeField(auto_now_add=True)
enddate = models.DateTimeField(auto_now_add=True)
transactions = models.ForeignKey(
"Transaction",
related_name="acc_no_transactions",
on_delete=models.CASCADE,
default="2",
)
balance = models.PositiveIntegerField(
null=True,
blank=True,
default=00,
)
def __str__(self):
return self.number
My views.py:
class CreateAccountnumberAPIView(CreateAPIView):
serializer_class = AccountnumberSerializer
permission_classes = {
IsAuthenticated,
}
def perform_create(self, serializer):
return serializer.save(user=self.request.user)
My serializers.py:
class AccountnumberSerializer(serializers.ModelSerializer):
class Meta:
model = Accountnumber
fields = (
"number",
"type",
"cdate",
"enddate",
"transactions",
"balance",
)
My stacktrace shows at perform_create() at views.py:
Internal Server Error: /api/v1/wallet/v1/account
Traceback (most recent call last):
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\utils.py", line 98, in inner
return func(*args, **kwargs)
sqlite3.IntegrityError: FOREIGN KEY constraint failed
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\core\handlers\exception.py", line 55, in inner
response = get_response(request)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\core\handlers\base.py", line 197, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
return view_func(*args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\views\generic\base.py", line 84, in view
return self.dispatch(request, *args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\views.py", line 509, in dispatch
response = self.handle_exception(exc)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\views.py", line 469, in handle_exception
self.raise_uncaught_exception(exc)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\views.py", line 480, in raise_uncaught_exception
raise exc
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\views.py", line 506, in dispatch
response = handler(request, *args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\generics.py", line 190, in post
return self.create(request, *args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\mixins.py", line 19, in create
self.perform_create(serializer)
File "C:\Users\USER\Documents\Dev\API\grand\wallet\views.py", line 69, in perform_create
return serializer.save(customuser=self.request.user)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\serializers.py", line
212, in save
self.instance = self.create(validated_data)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\rest_framework\serializers.py", line
962, in create
instance = ModelClass._default_manager.create(**validated_data)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
return getattr(self.get_queryset(),
name)(*args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\query.py", line 514, in create
obj.save(force_insert=True, using=self.db)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\base.py", line 806,
in save
self.save_base(
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\base.py", line 857,
in save_base
updated = self._save_table(
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\base.py", line 1000, in _save_table
results = self._do_insert(
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\base.py", line 1041, in _do_insert
return manager._insert(
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
return getattr(self.get_queryset(),
name)(*args, **kwargs)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\query.py", line 1434, in _insert
return query.get_compiler(using=using).execute_sql(returning_fields)
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\models\sql\compiler.py", line 1632, in execute_sql
self.connection.ops.fetch_returned_insert_columns(
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\backends\base\operations.py", line 208, in fetch_returned_insert_columns
return cursor.fetchone()
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\utils.py", line 97, in inner
with self:
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\utils.py", line 91, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:\Users\USER\Documents\Dev\API\grand\.venv\lib\site-packages\django\db\utils.py", line 98, in inner
return func(*args, **kwargs)
django.db.utils.IntegrityError: FOREIGN
KEY constraint failed
[13/Jan/2023 04:19:51] "POST /api/v1/wallet/v1/account HTTP/1.1" 500 183218

Answer 1

In your perform_create function you do the following:
def perform_create(self, serializer):
return serializer.save(user=self.request.user)
So you're saving the user variable to the user that made this request. That is fine, however, in your Accountnumber model, you store the user in the customuser field, not the user field.
Try to set your perform_create function to the following:
def perform_create(self, serializer):
return serializer.save(customuser=self.request.user)

Answer 2

All through, comments from my search for the answer have been that the IntegrityError of ForeignKey constriant failed mostly arises from the fact that you are trying to use a foreign key that does not yet exist and it was my case.
When creating an account number, I asked in my models.py that the field transactions be linked to the Transaction table foreign key WHICH DID NOT EXIST YET.
I, therefore, replaced the transaction field from referring to a ForeignKey to making it a CharField where I used the choices option and it worked.
Thanks, #Pavel Vergeev for editing my code
Thanks, #Ridape for pointing out an error which turns out was not the reason for the IntegrityError I was facing.