django model Form. Include fields from related models

A common practice is to use 2 forms to achieve your goal.

• A form for the User Model:

  class UserForm(forms.ModelForm):
      ... Do stuff if necessary ...
      class Meta:
          model = User
          fields = ('the_fields', 'you_want')
  

• A form for the Student Model:

  class StudentForm (forms.ModelForm):
      ... Do other stuff if necessary ...
      class Meta:
          model = Student
          fields = ('the_fields', 'you_want')
  

• Use both those forms in your view (example of usage):

  def register(request):
      if request.method == 'POST':
          user_form = UserForm(request.POST)
          student_form = StudentForm(request.POST)
          if user_form.is_valid() and student_form.is_valid():
              user_form.save()
              student_form.save()
  

• Render the forms together in your template:

  <form action="." method="post">
      {% csrf_token %}
      {{ user_form.as_p }}
      {{ student_form.as_p }}
      <input type="submit" value="Submit">
  </form>
  

Another option would be for you to change the relationship from OneToOne to ForeignKey (this completely depends on you and I just mention it, not recommend it) and use the inline_formsets to achieve the desired outcome.

An alternative method that you could consider is to create a custom user model by extending the AbstractUser or AbstractBaseUser models rather than using a one-to-one link with a Profile model (in this case the Student model). This would create a single extended User model that you can use to create a single ModelForm.

For instance one way to do this would be to extend the AbstractUser model:

from django.contrib.auth.models import AbstractUser

class Student(AbstractUser):

    phone = models.CharField(max_length = 25 )
    birthdate = models.DateField(null=True) 
    gender = models.CharField(max_length=1,choices = GENDER_CHOICES) 
    city = models.CharField(max_length = 50)
    personalInfo = models.TextField()
    # user = models.OneToOneField(User,unique=True)   <= no longer required

In settings.py file, update the AUTH_USER_MODEL

AUTH_USER_MODEL = 'appname.models.Student'

update the model in your Admin:

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin
from .models import Student

admin.site.register(Student, UserAdmin)

Then you can use a single ModelForm that has both the additional fields you require as well as the fields in the original User model. In forms.py

from .models import Student    

class StudentForm (forms.ModelForm):
    class Meta:
        model = Student
        fields = ['personalInfo', 'username']

A more complicated way would be to extend the AbstractBaseUser, this is described in detail in the docs.

However, I'm not sure whether creating a custom user model this way in order to have a convenient single ModelForm makes sense for your use case. This is a design decision you have to make since creating custom User models can be a tricky exercise.

From my understanding you want to update the username field of auth.User which is OneToOne relation with Student, this is what I would do...

class StudentForm (forms.ModelForm):

username = forms.Charfield(label=_('Username'))
class Meta:
    model = Student
    fields = ('personalInfo',)

def clean_username(self):
    # using clean method change the value
    # you can put your logic here to update auth.User
    username = self.cleaned_data('username')
    # get AUTH USER MODEL
    in_db = get_user_model()._default_manager.update_or_create(username=username)

hope this helps :)