IntegrityError at / - django

Question

I've been trying creating a user profile form using built-in User of django.contrib.auth.models. Everything is working fine but after filling the fields into the form(which is displaying), I am encountering an INTEGRITY ERROR AT / saying NOT NULL CONSTRAINT failed.
You can see this image using this link to know exactly what the error is showing.
This is my models.py file
from django.db import models
from django.contrib.auth.models import User
from django.core.validators import MaxValueValidator
# Create your models here.
class UserProfileInfo(models.Model):
user = models.OneToOneField(User,on_delete=models.CASCADE, null=True)
phone_number = models.PositiveIntegerField(validators=
[MaxValueValidator(9999999999)],blank=True)
def __str__(self): #This will print out this model
return self.user.username
This is my forms.py file.
from django import forms
from django.contrib.auth.models import User
from Login_Signup_Form.models import UserProfileInfo
class UserForm(forms.ModelForm):
password = forms.CharField(widget=forms.PasswordInput())
class Meta:
model=User
fields=('first_name','last_name','username','email','password',)
class UserProfileForm(forms.ModelForm):
class Meta:
model=UserProfileInfo #this is model
fields=('phone_number',)
This is my views.py file.
from django.shortcuts import render
from Login_Signup_Form.forms import UserForm,UserProfileForm
from Login_Signup_Form.models import UserProfileInfo
# Create your views here.
def index(request):
return render(request,'base.html')
def register(request):
registered=False
if request.method == 'POST':
user_form = UserForm(data=request.POST)
user_phone_number=UserProfileForm(data=request.POST)
if user_form.is_valid() and user_phone_number.is_valid():
user=user_form.save()
user.set_password(user.password)
user.save()
phone = user_phone_number.save()
phone.user=user
else:
#Printing the errors
print(user_form.errors,user_phone_number.errors)
else:
user_form = UserForm()
user_phone_number = UserProfileForm()
return render(request, 'base.html',{'user_form':user_form, '
phone_number':user_phone_number})

Answer 1

The error probably comes from an empty phone number in your form. You allow an empty phone_number in your form with blank=True but you don't allow it on the database level, you need to add null=True as well:
phone_number = models.PositiveIntegerField(validators=
[MaxValueValidator(9999999999)], blank=True, null=True)
See this great answer.
With blank=True the field is not required and the form will validate but it will raise the integrity error because null=True is not here. That wouldn't happen with a CharField though, the blank value would be stored as empty string. This only happens because of the PositiveIntegerField.