[Solved] django.db.utils.IntegrityError: FOREIGN KEY constraint failed

My models.py

class Order(models.Model):
    user = models.ForeignKey(User, blank=True, null=True, on_delete=models.PROTECT)
    customer_email = models.EmailField(blank=True, null=True, default=None)
    customer_name = models.CharField(max_length = 64, blank=True, null=True, default=None)
    customer_phone = models.CharField(max_length = 48, blank=True, null=True, default=None)
    customer_address = models.CharField(max_length = 128, blank=True, null=True, default=None)
    total_price = models.DecimalField(max_digits=10, decimal_places=2, default=0) #total price for all products in order
    comments = models.TextField(blank=True, null=True, default=None)
    status = models.ForeignKey(Status, on_delete=models.

    created = models.DateTimeField(auto_now_add=True, auto_now=False)
    updated = models.DateTimeField(auto_now_add=False, auto_now=True)

    def __str__(self):
        return "????? %s %s" % (self.id, self.status.name)

    class Meta:
        verbose_name = "?????"
        verbose_name_plural = "??????"

    def save(self, *args, **kwargs):
        super(Order, self).save(*args, **kwargs)

My views.py.

def checkout(request):
    session_key = request.session.session_key
    products_in_basket = ProductInBasket.objects.filter(session_key=session_key, is_active=True)
    form = CheckoutContactForm(request.POST or None)
    if request.POST:
        if form.is_valid():
            data = request.POST
            name = data.get("name", "34343434")
            phone = data["phone"]
            user, created = User.objects.get_or_create(username=phone, defaults={"first_name": name})

            order = Order.objects.create(user=user, customer_name=name, customer_phone=phone, status_id=1)
            for name, value in data.items():
                if name.startswith("product_in_basket_"):
                    product_in_basket_id = name.split("product_in_basket_")[1]
                    product_in_basket = ProductInBasket.objects.get(id=product_in_basket_id)

                    product_in_basket.nmb = value
                    product_in_basket.order = order


    return render(request, 'orders/checkout.html', locals())

The error:

Traceback (most recent call last):
  File "C:UsersNikita ShuliakAppDataLocalProgramsPythonPython37- 
 32libsite-packagesdjango-2.1rc1-py3.7.eggdjangocorehandlersexception.py",   line 34, in inner
    response = get_response(request)
  File "C:UsersNikita ShuliakAppDataLocalProgramsPythonPython37-32libsite-packagesdjango-2.1rc1-py3.7.eggdjangocorehandlersbase.py", line 126, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "C:UsersNikita ShuliakAppDataLocalProgramsPythonPython37-32libsite-packagesdjango-2.1rc1-py3.7.eggdjangocorehandlersbase.py", line 124, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:UsersNikita ShuliakDesktopNJBstartupordersviews.py", line 59, in checkout
    order = Order.objects.create(user=user, customer_name=name, customer_phone=phone, status_id=1)
  File "C:UsersNikita ShuliakAppDataLocalProgramsPythonPython37-32libsite-packagesdjango-2.1rc1-py3.7.eggdjangodbutils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:UsersNikita ShuliakAppDataLocalProgramsPythonPython37-32libsite-packagesdjango-2.1rc1-py3.7.eggdjangodbbackendsbasebase.py", line 239, in _commit
    return self.connection.commit()
django.db.utils.IntegrityError: FOREIGN KEY constraint failed


Maybe problem is here. The problem is appeared after i added some code which you can see in comments. “This last error suggests that the Status with pk=1 already exists, but your previous error suggests the contrary. Please add your Status model to your question; lets see if there are any other conditions to consider.”:

class Status(models.Model):
    name = models.CharField(max_length = 16, blank=True, null=True, default=None)
    is_active = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True, auto_now=False)
    updated = models.DateTimeField(auto_now_add=False, auto_now=True)

    def __str__(self):
        return "?????? %s" % self.name
Solution #1:

The error is in the line:

order = Order.objects.create(user=user, customer_name=name, customer_phone=phone, status_id=1)

You have to pass a status instance for the field status because it is a ForeignKey field. Just setting status_id to an integer won’t work.

I stand corrected, it can work; see this post.

Your error probably happens because either user (or user_id) or status (or status_id) are referencing instances that don’t exist in the related database table.

Are you sure that there is a status with pk=1? Does the operation Status.objects.get(pk=1) succeed?

Respondent: Ralf
Solution #2:

Try setting the named parameter of db_constraint of models.ForeignKey() to False(by default its True) like this:

status = models.ForeignKey(Status, on_delete=models.PROTECT,db_constraint=False)

This worked for me on a certain project the only issue will be that you will be unable to ensure the integrity of your db (e.g knowing whether all the Status objects referenced actually exist) but it makes sense if you’re working with legacy code.
Hope it helps.

Respondent: ang
Solution #3:

I see you didn’t save the instance “order”. —- order.save()

I think the solution is to save instaces to be saved.

Today, I had the same error message as you did. I realized that I forgot to save an instance in my code.
My code is different from your code, but I think you’re worth trying

Respondent: MorningMushroom
The answers/resolutions are collected from stackoverflow, are licensed under cc by-sa 2.5 , cc by-sa 3.0 and cc by-sa 4.0 .

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