Django：“user_id”列中的 null 值违反非空约束

Question

I'm using Postgresql and I have created the following models in my Django Project.

Models.py

User = settings.AUTH_USER_MODEL

Discount_Type=(
    ('$', '$'),
    ('%', '%'),
)

class Invoice(models.Model):
    ticket          = models.OneToOneField(Ticket,  related_name='invoice', blank=True,null=True, on_delete=models.CASCADE)
    updated_by      = models.ForeignKey(User, null=True, blank=True, related_name='invoice_editor', on_delete=models.SET_NULL)
    date_created    = models.DateTimeField(auto_now_add=True)
    date_updated    = models.DateTimeField(auto_now=True)
    is_paid        = models.BooleanField(default=False)
    
    federal_price = models.DecimalField(default=20.00, max_digits=6, decimal_places=2)
    federal_qty = models.PositiveIntegerField(default=1)
    federal_amount = models.DecimalField(null=True, blank=True, max_digits=6, decimal_places=2)
    state_price = models.DecimalField(default=20.00, max_digits=6, decimal_places=2)
    state_qty = models.PositiveIntegerField(default=1)
    state_amount = models.DecimalField(null=True, blank=True, max_digits=6, decimal_places=2)
    total_amount = models.DecimalField(null=True, blank=True, max_digits=6, decimal_places=2)
    discount = models.DecimalField(default=0.00, max_digits=6, decimal_places=2)
    discount_type  = models.CharField(default='$', max_length=5, choices=Discount_Type)
    discount_value = models.DecimalField(null=True, blank=True, max_digits=6, decimal_places=2)
    amount_payable = models.DecimalField(null=True, blank=True, max_digits=6, decimal_places=2)

    def __str__(self):
        return str(self.amount_payable)

    class Meta:
        ordering = ['-date_updated']

class Ticket(models.Model):
   tax_year        = models.CharField(max_length=50, default='2020')
   service         = models.CharField(max_length=50, default='Tax Filing')
   description     = models.TextField(max_length=1000, blank=True)
   customer        = models.ForeignKey(User, related_name='ticket_customer', on_delete=models.CASCADE)
   agents          = models.ManyToManyField(User, related_name="ticket_agents", blank=True)
   support         = models.ForeignKey(User, related_name='ticket_support', blank=True, null=True, on_delete=models.SET_NULL)
   preparation     = models.ForeignKey(User, related_name='ticket_preparation', blank=True, null=True, on_delete=models.SET_NULL)
   filing          = models.ForeignKey(User, related_name='ticket_filing', blank=True, null=True, on_delete=models.SET_NULL)


class Notification(models.Model):
    ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE, related_name="notification_ticket", blank=True, null=True)
    sender = models.ForeignKey(User, on_delete=models.SET_NULL, related_name="notification_from_user", blank=True, null=True)
    receivers = models.ManyToManyField(User, related_name="notification_to_user", blank=True)
    seen_by = models.ManyToManyField(User, related_name="notification_seen_by", blank=True)
    text_preview = models.CharField(max_length=255, blank=True)
    record_id = models.CharField(max_length=255, blank=True)
    date = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering: ['-date']
    def __str__(self):
        return self.text_preview

My forms.py

class TicketCreateForm(forms.ModelForm):
    class Meta:
        model = Ticket
        fields = ('tax_year', 'service', 'description',)
        widgets = {
          'tax_year': forms.Select(attrs={'class': 'form-control'}),
          'service': forms.Select(attrs={'class': 'form-control'}),
          'description': forms.Textarea(attrs={'rows':3, 'cols':60, 'class':'form-control'}),
        }

my views.py

def customer_ticket_create(request):
    form = TicketCreateForm()
    if request.method == 'POST':
        form = TicketCreateForm(request.POST or None)
        if form.is_valid():
            ticket = form.save(commit=False)
            ticket.customer = request.user  
            ticket.save()
            Invoice.objects.create( ticket=ticket, updated_by=request.user)
            return redirect('customer_home')

But I'm getting django.db.utils.IntegrityError: "user_id" violates not-null constraint. This error is because of Invoice.objects.create(ticket=ticket, updated_by=request.user) Without this line, my view is working fine. I'm getting the same error even when I tried to create the Invoice from SHELL.

Not sure why the view is not able to create Invoice. Can someone please help me?

So far I have tried the following solution from other similar questions: Updating the ForeignKey Model fields in Invoice Model with (null=True, Blank=True) Deleting the Migrations Files and Database. Running migrations and migrate and tried to create the Invoice again but still getting the same error.

Error Traceback

Environment:

Request Method: POST
Request URL: http://127.0.0.1:8000/ticket/create

Django Version: 3.1.4
Python Version: 3.8.5
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.sites',
 'django.forms',
 'accounts',
 'customers',
 'tickets',
 'message',
 'organizer',
 'documents',
 'agents',
 'invoices',
 'notifications',
 'workflow',
 'allauth',
 'allauth.account',
 'allauth.socialaccount',
 'intl_tel_input',
 'localflavor',
 'django_filters',
 'crispy_forms',
 'storages',
 'debug_toolbar',
 'django_extensions']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.locale.LocaleMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.common.BrokenLinkEmailsMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'csp.middleware.CSPMiddleware',
 'debug_toolbar.middleware.DebugToolbarMiddleware']



Traceback (most recent call last):
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)

The above exception (null value in column "user_id" violates not-null constraint
DETAIL:  Failing row contains (38, 18, null).
) was the direct cause of the following exception:
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\core\handlers\exception.py", line 47, in inner
    response = get_response(request)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\core\handlers\base.py", line 179, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\contrib\auth\decorators.py", line 21, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "C:\Users\Sai Maruthi\Documents\Dev\lappy\src\accounts\decorators.py", line 20, in wrapper_func
    return view_func(request, *args, **kwargs)
  File "C:\Users\Sai Maruthi\Documents\Dev\lappy\src\tickets\views.py", line 61, in customer_ticket_create
    Invoice.objects.create(
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\query.py", line 447, in create
    obj.save(force_insert=True, using=self.db)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\base.py", line 753, in save
    self.save_base(using=using, force_insert=force_insert,
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\base.py", line 801, in save_base
    post_save.send(
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\dispatch\dispatcher.py", line 177, in send
    return [
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\dispatch\dispatcher.py", line 178, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "C:\Users\Sai Maruthi\Documents\Dev\lappy\src\invoices\signals.py", line 88, in invoice_update_notification
    notification.seen_by.set([ticket.customer, ticket.support, ticket.preparation, ticket.filing, ticket.fbar, ticket.itin, ticket.extra])
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\fields\related_descriptors.py", line 1015, in set
    self.add(*new_objs, through_defaults=through_defaults)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\fields\related_descriptors.py", line 950, in add
    self._add_items(
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\fields\related_descriptors.py", line 1130, in _add_items
    self.through._default_manager.using(db).bulk_create([
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\query.py", line 506, in bulk_create
    returned_columns = self._batched_insert(
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\query.py", line 1277, in _batched_insert
    self._insert(item, fields=fields, using=self.db, ignore_conflicts=ignore_conflicts)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\query.py", line 1254, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\models\sql\compiler.py", line 1397, in execute_sql
    cursor.execute(sql, params)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\debug_toolbar\panels\sql\tracking.py", line 198, in execute
    return self._record(self.cursor.execute, sql, params)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\debug_toolbar\panels\sql\tracking.py", line 133, in _record
    return method(sql, params)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 98, in execute
    return super().execute(sql, params)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 66, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 75, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Users\Sai Maruthi\.virtualenvs\lappy-FT-EdR8P\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)

Exception Type: IntegrityError at /ticket/create
Exception Value: null value in column "user_id" violates not-null constraint
DETAIL:  Failing row contains (38, 18, null).

EDIT-1

@receiver(post_save, sender=Invoice)
def invoice_update_notification(sender, instance, **kwargs):
    if instance.is_paid:
        ticket = instance.ticket
        notification = Notification.objects.create(
            ticket=ticket,
            sender=instance.updated_by,
            text_preview= f'Received Payment- {instance.amount_payable}',
            record_id=instance.id,)
        notification.seen_by.set([ticket.customer, ticket.support, ticket.preparation, ticket.filing])
    else:
        ticket = instance.ticket
        notification = Notification.objects.create(
            ticket=ticket,
            sender=instance.updated_by,
            text_preview= f'Invoice Updated - {instance.amount_payable}',
            record_id=instance.id,)
        notification.seen_by.set([ticket.customer, ticket.support, ticket.preparation, ticket.filing])

Answer 1

ticket.support , ticket.preparation and ticket.filing are all nullable meaning that any of them could be None . You need to filter out the fields that are null.

The built-in function filter can be used to filter out items from a list that are "falsy" like None by passing None as the first argument

users = list(filter(None, [ticket.customer, ticket.support, ticket.preparation, ticket.filing]))
notification.seen_by.set(users)