Error when registering user in Django

Question

When I wish to register a new user in Django, I receive the following warning: UNIQUE constraint failed: polls_usuario.matriculaUsuario

What might be going on?

py views.

def registrar(request):
    if request.method == 'POST':
        form = SignUpForm(request.POST)
        usuario_form = UsuarioForm(request.POST)
        if form.is_valid() and usuario_form.is_valid():
            user = form.save(commit=False)
            user.refresh_from_db()  # load the profile instance created by the signal
            user.usuario.matriculaUsuario = form.cleaned_data.get('matriculaUsuario')
            usuario_form.save()
            user.save()
            raw_password = form.cleaned_data.get('password1')
            user = authenticate(username=user.username, password=raw_password)
            login(request,user)
            return render(request, 'polls/index.html', user)
            #return HttpResponseRedirect(reverse('/')) 
            #return redirect('/')
    else:
        form = SignUpForm()
        usuario_form = UsuarioForm()
    return render(request, 'polls/registrar.html', {'form': form , 'usuario_form':usuario_form})

Forms.py

class UsuarioForm(forms.ModelForm):
    class Meta:
        model = Usuario
        fields = ('matriculaUsuario',)

class SignUpForm(UserCreationForm):
    first_name = forms.CharField(label='Primeiro Nome',max_length=30, required=False, help_text='Opcional.')
    last_name = forms.CharField(label='Último Nome',max_length=30, required=False, help_text='Opcional.')
    email = forms.EmailField(label='E-mail',max_length=254, help_text='Informe o seu e-mail (Requerido)')   
    username = forms.CharField(label='Nome de usuário', min_length=4, max_length=150)
    password1 = forms.CharField(label='Senha', widget=forms.PasswordInput)
    password2 = forms.CharField(label='Confirmação da senha', widget=forms.PasswordInput)

    matriculaUsuario = forms.CharField(label='Matrícula',max_length=12,validators=[ validators.RegexValidator(re.compile('^[0-9]{12}$'), _('Digite uma matrícula válida'), _('invalid'))])

    class Meta:
        model = User
        fields = ['first_name', 'last_name','username','matriculaUsuario','email','password1', 'password2',] 
    def clean_username(self):
        username = self.cleaned_data['username'].lower()
        r = User.objects.filter(username=username)
        if r.count():
            raise  ValidationError("Nome de usuário já cadastrado")
        return username

    def clean_email(self):
        email = self.cleaned_data['email'].lower()
        r = User.objects.filter(email=email)
        if r.count():
            raise  ValidationError("E-mail já cadastrado")
        return email

    def clean_password2(self):
        password1 = self.cleaned_data.get('password1')
        password2 = self.cleaned_data.get('password2')

        if password1 and password2 and password1 != password2:
            raise ValidationError("Senhas não conferem")

        return password2

    def save(self, commit=True):
        user = User.objects.create_user(
            self.cleaned_data['username'],
            self.cleaned_data['email'],
            self.cleaned_data['password1']
        )
        return user
class EditProfileForm(forms.ModelForm):
    first_name = forms.CharField(label='Nome')
    last_name = forms.CharField(label='Sobrenome')
    username = forms.CharField(min_length=4, max_length=150,help_text=("Insira um novo nome de usuário"), label='Nome de usuário')
    email = forms.EmailField(label='E-mail')
    matriculaUsuario = forms.CharField(label='Matrícula', max_length=12,validators=[ validators.RegexValidator(re.compile('^[0-9]{12}$'), _('Digite uma matrícula válida'), _('invalid'))])
    class Meta:
        model = User
        fields = ['first_name', 'last_name','username','matriculaUsuario','email'] 

py.models

class Usuario(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE,null=True)
    matriculaUsuario = models.CharField(default='000000000000',max_length=12,primary_key=True,null=False,help_text=_('São requeridos os 12 dígitos referentes à sua matrícula'), validators=[ validators.RegexValidator(re.compile('^[0-9]{12}$'), _('Digite uma matrícula válida'), _('invalid'))])
    def __str__(self):
 return self.user.username
        @receiver(post_save, sender=User)
    def update_user_usuario(sender, instance, created, **kwargs):
        if created:
            Usuario.objects.create(user=instance)
        instance.usuario.save()

    @receiver(post_save, sender=User)
    def create_user_usuario(sender, instance, created, **kwargs):
        if created:
            Usuario.objects.create(user=instance)
    post_save.connect(create_user_usuario,sender=User)
@receiver(post_save, sender=User)
    def save_user_usuario(sender, instance, created,**kwargs):
        if created:
            instance.usuario.save()

EDIT

Answer 1

I understand you need to just extend the User adding some fields, without necessarily changing anything in the auth, I mean, you’re not customizing the authentication, right? but I couldn’t understand what you wanted to do in the model Usuario, in my view should be simpler, either you really customize everything or just extend the class User embedded in Django, I’m going to give a example of the documentation itself (making a small adaptation to your context, but calling your student) by placing the extended class in admin, which you did not do:

py.models

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

class Aluno(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    # Adicionando os campos (adicione qtos precisar)
    matricula = models.CharField('Matrícula', max_length=12)

admin py.

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin as BaseUserAdmin
from django.contrib.auth.models import User
from .models import Aluno

class AlunoInline(admin.StackedInline):
    model = Aluno
    can_delete = False
    verbose_name = 'Informações Pessoais'

class UserAdmin(BaseUserAdmin):
    inlines = (AlunoInline,)

# Re-register UserAdmin
admin.site.unregister(User)
admin.site.register(User, UserAdmin)

@admin.register(Aluno)
class AlunoAdmin(admin.ModelAdmin):
    model = Aluno
    list_display = ('user', 'matricula',)

Okay, now go to the Django admin and you’ll have:

You can add students (user) either by auth (AUTHENTICATION AND AUTHORIZATION) or by USERS (Students)

Although repl.it still has some limitations with Django, left working there, to run you need to make a Fork, Migrations and create the superuser (just follow the instructions of the CLI panel on the lower right side).