How to link an existing model with user model in Django

Question

This is a quite simple question I think, but I'm new with Django and searching the best/correct way to do things. So forgive me if I'm asking stupid questions.

I have a model called Person in my Django app. It contains just basic info of a person, no personal data involved yet:

class Person(models.Model):

    birthday = models.DateField(null=True)

    gender = models.CharField(max_length=10)

    height = models.CharField(max_length=3)

    weight = models.CharField(max_length=3)

Now I want to also add a feature for the person to register and log in. What is the correct way to do this? Many tutorials seem to suggest using the forms.py file, like this for example:

from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User

class RegisterForm(UserCreationForm):
    birthdate = forms.DateField()
    discord_id = forms.CharField(max_length=100, help_text='Discord ID')
    zoom_id = forms.CharField(max_length=100, help_text='Zoom ID')

    class Meta:
        model = User
        fields = ["username", "password1", "password2", "birthdate", "email", "discord_id", "zoom_id"]

How would I use/link my existing Person model with this built in User -model? Or do I need a separate model in Models.py at all? Do I just create the User-model like above in the forms.py and add my custom fields into it?

Answer 1

You can refer the django docs on extending user model:

https://docs.djangoproject.com/en/3.2/topics/auth/customizing/#extending-the-existing-user-model

There are two approaches. You can have a OneToOne relation with your model to django user model to add additional fields. Or you can extend the abstract user model from django to create a custom user.

from django.contrib.auth.models import AbstractUser

    class Person(AbstractUser):
        birthday = models.DateField(null=True)

        gender = models.CharField(max_length=10)

        height = models.CharField(max_length=3)

        weight = models.CharField(max_length=3)

Also you need to mark the custom user in settings:

AUTH_USER_MODEL = 'myapp.Person'

Then that model can be used in the form:

from django.contrib.auth.forms import UserCreationForm
from .models import Person

class RegisterForm(UserCreationForm):
    birthdate = forms.DateField()
    discord_id = forms.CharField(max_length=100, help_text='Discord ID')
    zoom_id = forms.CharField(max_length=100, help_text='Zoom ID')

    class Meta:
        model = Person
        fields = ["username", "password1", "password2", "birthdate", "email", "discord_id", "zoom_id"]

Alternatively you can do OneToOne relation:

from django.contrib.auth.models import User

class Person(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)

    birthday = models.DateField(null=True)

    gender = models.CharField(max_length=10)

    height = models.CharField(max_length=3)

    weight = models.CharField(max_length=3)