(django) I want to create a specified model instance when user was created based on their role

Question

(i.e. if user role is passenger create instance for passenger and if user is driver create respective instance for driver and etc.)I think it's a matter of signals but I need someone to show me the logical ways todo it.)

class MyUser(AbstractUser):
    first_name = models.CharField(max_length=100,null=True)
    last_name = models.CharField(max_length=100,null=True)
    email = models.EmailField(null=True)
    ROLE = (
                    ('Passenger', 'Passenger'),
                    ('TSHO', 'TSHO'),
                    ('Employee', 'Employee'),
                    ('Driver', 'Driver'),
                   )
   role = models.CharField(max_length=200, choices=ROLE)

--this the model in which I want to create the instance if user role is driver

class Driver(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on delete=models.CASCADE, related_name='employee')
    occupation=models.CharField(max_length=200,null=True)
    address=models.CharField(max_length=100,null=True)
    house_no=models.CharField(max_length=100,null=True)

--and this the model in which I want to create the instance if user role is passenger

class Passenger(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE,related_name='passenger')
    sex = models.CharField(max_length=200, choices=(('male', 'male'), ('female', 'female')),null=True)
    bio = models.TextField(max_length=500, blank=True)
    location = models.CharField(max_length=30, blank=True)
    birth_date = models.DateField(null=True, blank=True)

score 0 · Answer 1 · answered Jul 02 '21 at 17:09

There are two approaches, one using signals and another one is overriding the save method. I would prefer the latter, since it's less error-prone and more obvious.

class MyUser(AbstractUser):
  ...
  def save(self, *args, **kwargs):
    from app.models import Driver, Passenger  # avoid circular import issues

    adding = self._state.adding
    super().save(*args, **kwargs)
    if not adding:
        return

    if self.role == 'Driver': # should use models.TextChoices to avoid magic strings
        Driver.objects.create(user=self)
    elif self.role == 'Passenger':
        Passenger.objects.create(user=self)

Docs on models.TextChoices

P.S. Please read this question about using null=True - you are doing it wrong.

(django) I want to create a specified model instance when user was created based on their role

1 Answers1