Why does the 'value must be an integer' error appear when saving formset?

Question

Django

For some unknown reason, janga can't create a new id

class Data(models.Model):
    field1 = models.CharField(max_length=45, blank=True, null=True)
    field2 = models.CharField(max_length=45, blank=True, null=True)
    field3 = models.IntegerField(blank=True, null=True)
    field4 = models.DecimalField(max_digits=10, decimal_places=0, blank=True, null=True)
    field5 = models.DecimalField(max_digits=10, decimal_places=2, blank=True, null=True)
    field6 = models.IntegerField(blank=True, null=True)
    field7 = models.DateField(blank=True, null=True)
    field8 = models.CharField(max_length=255, blank=True, null=True)
form.py

class DataForm(forms.ModelForm):
    class Meta:
        model = Data
        fields = '__all__'
views.py

data = Data.objects.all()
DataFormSet = modelformset_factory(Data, exclude=('field6',), form=DataForm)

if request.method == 'POST':
    data_form = DataFormSet(request.POST, request.FILES)

    if data_form.is_valid():
        data_form.save()
else:
    data_form = DataFormSet(queryset=data)

{{ formset_advance.management_form }}

                        {% for form_advance in formset_advance %}
                        {{ form_advance.idpub_royalties_advances }}
                          <tr class="ppradvtbl">
                            <td>{{ form_advance.advance_num }}</td>
                            <td>{{ form_advance.currency_amount }}</td>
                            <td>{{ form_advance.home_currency_amount }}</td>
                            <td><span class="datePicker">{{ form_advance.invoice_rec_date }}</span></td>
                            <td>{{ form_advance.pay_question }}</td>
                            <td>{{ form_advance.advance_note }}</td>
                          </tr>
                        {% endfor %}

ValidationError at /url
[u"'' value must be an integer."]

Traceback:
File "/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  132.                     response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/lib/python2.7/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
  22.                 return view_func(request, *args, **kwargs)
File "/dimo/Project/dimo/views.py" in royalties_rights
  440.         if royalties_advance.exists() and formset_advance.is_valid():
File "/lib/python2.7/site-packages/django/forms/formsets.py" in is_valid
  304.         self.errors
File "/lib/python2.7/site-packages/django/forms/formsets.py" in errors
  278.             self.full_clean()
File "/lib/python2.7/site-packages/django/forms/formsets.py" in full_clean
  326.             form = self.forms[i]
File "/lib/python2.7/site-packages/django/utils/functional.py" in __get__
  59.         res = instance.__dict__[self.name] = self.func(instance)
File "/lib/python2.7/site-packages/django/forms/formsets.py" in forms
  142.         forms = [self._construct_form(i) for i in range(self.total_form_count())]
File "/lib/python2.7/site-packages/django/forms/models.py" in _construct_form
  586.             pk = to_python(pk)
File "/lib/python2.7/site-packages/django/db/models/fields/__init__.py" in to_python
  969.                 params={'value': value},

Exception Type: ValidationError at /url
Exception Value: [u"'' value must be an integer."]

Answer 1

Show template
If forms are displayed manually, form.id must be specified

{{ formset_advance.management_form }}
  {% for form_advance in formset_advance %}
     {{ form_advance.id }}
     {{ form_advance.idpub_royalties_advances }}
     <tr class="ppradvtbl">
       <td>{{ form_advance.advance_num }}</td>
       <td>{{ form_advance.currency_amount }}</td>
       <td>{{ form_advance.home_currency_amount }}</td>
       <td><span class="datePicker">{{ form_advance.invoice_rec_date }}</span></td>
       <td>{{ form_advance.pay_question }}</td>
       <td>{{ form_advance.advance_note }}</td>
     </tr>
  {% endfor %}