Django unique constraint not working

Question

I want to display error whenever user try to create object with the same name. I want firm name to be unique. Tried but issue remains. Django should display error in the form but why I am getting this.????

Firm model:

class Firm(models.Model):
    name = models.TextField(
        verbose_name='firm name',
        max_length=100, unique=True
    )
    address = models.TextField(
        max_length=100
    )
    phone_no_1 = models.CharField(
        max_length=10, null=True, blank=True
    )
    phone_no_2 = models.CharField(
        max_length=10, null=True, blank=True
    )
    reg_no = models.TextField(
        max_length=25, null=True, blank=True
    )

But instead I am getting this.

Traceback:
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\core\handlers\base.py" in get_response
  111.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\views\generic\base.py" in view
  69.             return self.dispatch(request, *args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\utils\decorators.py" in _wrapper
  29.             return bound_func(*args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\contrib\auth\decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\utils\decorators.py" in bound_func
  25.                 return func.__get__(self, type(self))(*args2, **kwargs2)
File "C:\Users\PrImE\workspace\kaizentech\egirvi\dev\egirvi\girvi\utils.py" in dispatch
  14.         return super(LoginRequiredMixin, self).dispatch(*args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\views\generic\base.py" in dispatch
  87.         return handler(request, *args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\views\generic\edit.py" in post
  207.         return super(BaseCreateView, self).post(request, *args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\views\generic\edit.py" in post
  173.             return self.form_valid(form)
File "C:\Users\PrImE\workspace\kaizentech\egirvi\dev\egirvi\girvi\views\create_views\create_firm_view.py" in form_valid
  16.         super(CreateFirmView, self).form_valid(form)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\views\generic\edit.py" in form_valid
  149.         self.object = form.save()
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\forms\models.py" in save
  457.                              construct=False)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\forms\models.py" in save_instance
  103.         instance.save()
File "C:\Users\PrImE\workspace\kaizentech\egirvi\dev\egirvi\girvi\models\firm.py" in save
  29.         return super(Firm, self).save(*args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\base.py" in save
  590.                        force_update=force_update, update_fields=update_fields)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\base.py" in save_base
  618.             updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\base.py" in _save_table
  699.             result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\base.py" in _do_insert
  732.                                using=using, raw=raw)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\manager.py" in manager_method
  92.                 return getattr(self.get_queryset(), name)(*args, **kwargs)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\query.py" in _insert
  921.         return query.get_compiler(using=using).execute_sql(return_id)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\models\sql\compiler.py" in execute_sql
  920.                 cursor.execute(sql, params)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\backends\utils.py" in execute
  81.             return super(CursorDebugWrapper, self).execute(sql, params)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\backends\utils.py" in execute
  65.                 return self.cursor.execute(sql, params)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\utils.py" in __exit__
  94.                 six.reraise(dj_exc_type, dj_exc_value, traceback)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\backends\utils.py" in execute
  65.                 return self.cursor.execute(sql, params)
File "C:\Users\PrImE\envs\kaizentech\lib\site-packages\django\db\backends\sqlite3\base.py" in execute
  485.         return Database.Cursor.execute(self, query, params)

Exception Type: IntegrityError at /add_firm/
Exception Value: column name is not unique

View:

class CreateFirmView(LoginRequiredMixin, CreateView):
    form_class = CreateFirmForm
    http_method_names = ['get', 'post']
    success_url = reverse_lazy('girvi:find_customer')
    template_name = 'create_templates/create_firm.html'

    def form_valid(self, form):
        from django.shortcuts import HttpResponse
        super(CreateFirmView, self).form_valid(form)
        return HttpResponse(
            '''
            <script>
                window.close();
                window.onunload = refreshParent; function refreshParent() {
                window.opener.location.reload();
                }
            </script>
            '''
        )

Form:

class CreateFirmForm(forms.ModelForm):
    from girvi.utils import validators
    phone_no_1 = forms.CharField(
        label='Phone No. 1', required=False, validators=[
            validators.get('only_numbers'), validators.get('min_value')(10)
        ],
        widget=forms.TextInput(
            attrs={'placeholder': 'Mobile Number', 'class': 'form-control'}
        )
    )
    phone_no_2 = forms.CharField(
        label='Phone No. 2 ', required=False, validators=[
            validators.get('only_numbers'), validators.get('max_value')(10), validators.get('max_value')(10)
        ],
        widget=forms.TextInput(
            attrs={'placeholder': 'Mobile Number', 'class': 'form-control'}
        )
    )

    class Meta:
        model = Firm
        fields = '__all__'
        widgets = {
            'name': forms.TextInput(
                attrs={'autofocus': 'true', 'class': 'form-control', 'placeholder': 'Firm Name'}
             ),
            'address': forms.TextInput(
                attrs={'class': 'form-control', 'placeholder': 'Address'}
            ),
            'reg_no': forms.TextInput(
                attrs={'class': 'form-control', 'placeholder': 'Reg No.'}
            )
        }

SQL :

CREATE TABLE "girvi_firm" ("id" integer NOT NULL PRIMARY KEY AUTOINCREMENT, "name" varchar(100) NOT NULL UNIQUE, "address" text NOT NULL, "phone_no_1" varchar(10) NULL, "phone_no_2" varchar(10) NULL, "reg_no" text NULL)

Answer 1

This error is thrown by database.

But django ModelForm will process unique costraint automatically.

Just don't forget to call clean() method of the parent form:

from django import forms


class FirmForm(forms.ModelForm):
    class Meta:
        model = Firm

    def clean(self):
        # do some your stuff here
        # don't forget to call super().clean
        return super(FirmForm, self).clean()

As it written in django docs :

The ModelForm.clean() method sets a flag that makes the model validation step validate the uniqueness of model fields that are marked as unique, unique_together or unique_for_date|month|year.
If you would like to override the clean() method and maintain this validation, you must call the parent class's clean() method.