[FIXED] TypeError: Field 'id' expected a number but got (<Group: customer>, True) DJANGO ERROR

Issue

I am learning how to use Django through a small project ... I am trying to connect my project to a Postgreslq database and I get this type of error

models.py

from django.db import models
from django.db.models.deletion import SET_NULL
from django.contrib.auth.models import User

class Customer(models.Model):
    user = models.OneToOneField(User, null=True, blank=True, on_delete=models.CASCADE)
    name = models.CharField(max_length=200, null=True)
    phone = models.CharField(max_length=200, null=True)
    email = models.CharField(max_length=200, null=True)
    profile_pic = models.ImageField(default='profile1.png',null=True, blank=True)
    date_created = models.DateTimeField(auto_now_add=True, null=True)
    
    def __str__(self):
        return self.name

class Tag(models.Model):
    name = models.CharField(max_length=200, null=True)
    
    def __str__(self):
        return self.name 

class Product(models.Model):
    CATEGORY = (
            ('Indoor', 'Indoor'),
            ('Out Door', 'Out Door'),
            ) 
    
    name = models.CharField(max_length=200, null=True)
    prince = models.FloatField(null=True)
    category = models.CharField(max_length=200, null=True, choices=CATEGORY)
    description = models.CharField(max_length=200, null=True, blank=True)
    date_created = models.DateTimeField(auto_now_add=True, null=True)
    tags = models.ManyToManyField(Tag)

    def __str__(self):
        return self.name

class Order(models.Model):
    STATUS = (
            ('Pending', 'Pending'),
            ('Out for delivery', 'Out for delivery'),
            ('Delivered', 'Delivered'),
            )
    
    customer = models.ForeignKey(Customer, null=True, on_delete=SET_NULL)
    product = models.ForeignKey(Product, null=True, on_delete=SET_NULL)
    status = models.CharField(max_length=200, null=True, choices=STATUS)
    date_created = models.DateTimeField(auto_now_add=True, null=True)
    note = models.CharField(max_length=1000, null=True)

    def __str__(self):
        return self.product.name

signals.py

from django.db.models.signals import post_save
from django.contrib.auth.models import User, Group
from .models import Customer

def customer_profile(sender, instance, created, **kwagrs):
    if created:
        group = Group.objects.get_or_create(name='customer')
        instance.groups.add(group)
        Customer.objects.create(
                user = instance,
                name = instance.username
            )
        print('Profile created.!')

post_save.connect(customer_profile, sender= User)

settings.py

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'DEMO_TEST',
        'USER' : 'postgres',
        'HOST': 'localhost',
        'PASSWORD':'Elohim150..',
        'PORT': '5432',
    }
}

Traceback

  File "manage.py", line 22, in <module>
    main()
  File "manage.py", line 18, in main
    execute_from_command_line(sys.argv)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\core\management\__init__.py", line 419, in execute_from_command_line
    utility.execute()
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\core\management\__init__.py", line 413, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\core\management\base.py", line 354, in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\contrib\auth\management\commands\createsuperuser.py", line 79, in execute
    return super().execute(*args, **options)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\core\management\base.py", line 398, in execute
    output = self.handle(*args, **options)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\contrib\auth\management\commands\createsuperuser.py", line 189, in handle
    self.UserModel._default_manager.db_manager(database).create_superuser(**user_data)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\contrib\auth\models.py", line 163, in create_superuser
    return self._create_user(username, email, password, **extra_fields)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\contrib\auth\models.py", line 146, in _create_user
    user.save(using=self._db)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\contrib\auth\base_user.py", line 67, in save
    super().save(*args, **kwargs)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\base.py", line 726, in save
    self.save_base(using=using, force_insert=force_insert,
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\base.py", line 774, in save_base
    post_save.send(
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\dispatch\dispatcher.py", line 180, in send
    return [
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\dispatch\dispatcher.py", line 181, in <listcomp>
    (receiver, receiver(signal=self, sender=sender, **named))
  File "C:\Users\l\Desktop\django-course\Django(02-09-21)\crm1\accounts\signals.py", line 8, in customer_profile
    instance.groups.add(group)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\fields\related_descriptors.py", line 950, in add
    self._add_items(
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\fields\related_descriptors.py", line 1126, in _add_items
    target_ids = self._get_target_ids(target_field_name, objs)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\fields\related_descriptors.py", line 1073, in _get_target_ids
    target_ids.add(target_field.get_prep_value(obj))
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\fields\related.py", line 977, in get_prep_value
    return self.target_field.get_prep_value(value)
  File "C:\Users\l\anaconda3\envs\myenv\lib\site-packages\django\db\models\fields\__init__.py", line 1825, in get_prep_value
    raise e.__class__(
TypeError: Field 'id' expected a number but got (<Group: customer>, True).
    

Maybe there is an error in one of the fields that I have in the 'Customer' model, but I really don't understand one hundred percent what the error is because I am inexperienced ... Can someone show me the error and explain the solution to me, it would be very helpful. !!

Solution

get or create in django return tuple. (object, created)

https://docs.djangoproject.com/en/4.0/ref/models/querysets/#get-or-create

get_or_create(defaults=None, **kwargs)¶ A convenience method for looking up an object with the given kwargs (may be empty if your model has defaults for all fields), creating one if necessary. Returns a tuple of (object, created), where object is the retrieved or created object and created is a boolean specifying whether a new object was created.

try this

def customer_profile(sender, instance, created, **kwagrs):
    if created:
        group, is_created = Group.objects.get_or_create(name='customer')
        if is_created:
            instance.groups.add(Group.objects.get(name='customer'))
        else:
            instance.groups.add(group)
        Customer.objects.create(
                user = instance,
                name = instance.username
            )
        print('Profile created.!')

Refer https://docs.djangoproject.com/en/3.2/topics/db/examples/many_to_many/ for more details

Answered By - rahul.m