Foreign key defaults to Auth User in Django

Question

I'm using Django 1.11

I have a business model.

class Business(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    name = models.CharField(max_length=200)
    business_type = models.ForeignKey(BusinessType, on_delete=models.CASCADE)

    class Meta:
        verbose_name = 'business'
        verbose_name_plural = 'businesses'
        db_table = 'businesses'

    def __str__(self):
        return self.name

When I run python3 manage.py makemigration business It gives

You are trying to add a non-nullable field 'user' to business without a default;

I want to set this field to use the logged in user id as foreign key by default.

How to use Auth user id as default for user specific data record?

Edit 2

Business create view views.py

class BusinessCreate(CreateView):
    model = Business
    fields = ['name', 'business_type']

    def get_context_data(self, **kwargs):
        data = super(
            BusinessCreate,
            self
        ).get_context_data(**kwargs)

        if self.request.POST:
            data['business_address'] = BusinessAddressFormSet(self.request.POST)
        else:
            data['business_address'] = BusinessAddressFormSet()
        return data

    def form_valid(self, form):
        context = self.get_context_data()
        business_address = context['business_address']
        with transaction.atomic():
            self.object = form.save()

            if business_address.is_valid():
                business_address.instance = self.object
                business_address.save()

        return super(BusinessCreate, self).form_valid(form)

    def get_success_url(self):
        messages.success(self.request, 'Business Added Successfully')
        return reverse('business:list')

Astik Anand · Accepted Answer · 2017-09-21T12:09:58.257

3

You need to provide the default user in case of ForeignKey coz that field is non nullable.

user = models.ForeignKey(User, on_delete=models.CASCADE, default=1)

Update After Comment

def form_valid(self, form):
    form.instance.user = self.request.user
    return super(BusinessCreate, self).form_valid(form)

edited Sep 21 '17 at 12:09

answered Sep 21 '17 at 11:57

Astik Anand

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2

if user with pk=1 is not exists? – Brown Bear Sep 21 '17 at 12:00
1

I want to set default to user id who is logged in – Anuj TBE Sep 21 '17 at 12:02
You can not do that, for that you need request variable which can be accessed in model. – Astik Anand Sep 21 '17 at 12:05
@AnujTBE, Feel privileged to help you. Thanks a lot. – Astik Anand Sep 21 '17 at 12:29

score 1 · Answer 2 · answered Sep 21 '17 at 12:00

1

There's no way to do that. The current user only makes sense in the context of a http request. Migrations cannot rely on that context. You must instead pass the current user explicitly when creating new Business instances in a view function.

answered Sep 21 '17 at 12:00

Håken Lid

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I have updated question with create view. How to pass explicitly? – Anuj TBE Sep 21 '17 at 12:07
You can override `form_valid` and add the current user to the form. https://stackoverflow.com/a/34239078/1977847 – Håken Lid Sep 21 '17 at 12:11

Foreign key defaults to Auth User in Django

2 Answers2