Prevent duplicate entries on user level

Using Django Forms & APIs
1

Hello!
I am looking to write a validator that will prevent a user from inputting duplicate entries, but would allow duplicate entries in the overall table. For example, let’s say each of my users is a company that needs to input customer info. If two of these companies have the same customer, they should be able to have the same data in their own user-owned rows without throwing an error. On the other hand, I’d like to prevent an individual user from creating duplicates. I had tried the unique_together option on the model only to have it fail because of the owner field being a foreign key. Additionally, the owner field in the form is excluded. I have read through a bunch of the documentation and am still a bit lost. I am new to coding and Django so if anyone could offer some insights, it would be greatly appreciated. TIA

views.py
class CustomerCreate(OwnerCreateView):
    model = Customer
    form_class = CustomerCreateForm
    template_name = ...
    success_url = ...
    
class CustomerUpdate(OwnerUpdateView):
    model = Customer
    form_class = CustomerUpdateForm
    template_name = ...
    success_url = ...
	
owner.py
class OwnerCreateView(LoginRequiredMixin, CreateView):
    def form_valid(self, form):
        form.instance.owner = self.request.user
        return super().form_valid(form)

class OwnerUpdateView(LoginRequiredMixin, UpdateView):
    def get_queryset(self):
        qs = super(OwnerUpdateView, self).get_queryset()
        return qs.filter(owner=self.request.user)
		
models.py
class Customer(models.Model:
	first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    company = models.CharField(max_length=128, blank=True)
	owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
		
forms.py
class CustomerCreateForm(ModelForm):
	class Meta:
		model = Customer
		exclude = ('owner',)
		
class CustomerUpdateForm(ModelForm):
	class Meta:
		model = Customer
		exclude = ('owner',)
2

That should work. The owner field being a foreign key should not prevent its usage in a unique_together clause. Please post the code you tried along with the complete error (and traceback) you received while trying it.
(Or, more appropriately, you should probably be using a UniqueConstraint. See Model Meta options | Django documentation | Django)

3

When I first tried the code below in models.py, it would blow up. I then simplified my form to the code mentioned above to avoid confusing myself with crispy-form stuff. I can no longer duplicate that condition. Currently, the unique_together allows a duplicate post when the “owner” field is listed but If I take “owner” out, it will produce and error, but for all users. I did not know about UniqueConstraint and will read up on it. Thank you for your help!

class Customer(models.Model:
    first_name = models.CharField(max_length=50)
    last_name = models.CharField(max_length=50)
    company = models.CharField(max_length=128, blank=True)
    owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)

    class Meta:
        unique_together = ["first_name", "last_name", "owner"]
4

After a bit more digging, I think the issue is with validation not running on excluded fields. I’ll have to figure out a work around tomorrow.