what causes the weird "UNIQUE constraint failed: auth_user.username" error? - django

Question

I try to insert data in user model into other model by one to one relationship. In specific, I want insert username,email and password attributes of User into other models.In Addtional, I intend to create both User model and other model in one form. So, I override the save method in modelform. It works partially and be able to insert data in both models and databases, except throw a UNIQUE constraint failed: auth_user.username error.
In models.py
class Staff(models.Model):
yes_or_no = ((True, 'Yes'),(False, 'No'))
male_or_female = ((True,'Male'),(False,'Female'))
user = models.OneToOneField(User, unique=True)
gender = models.BooleanField(default = True, choices = male_or_female)
birthday = models.DateField(default =None,blank = False, null = False)
created = models.DateTimeField(default=datetime.now, blank=True)
authorized = models.BooleanField(default=False,choices = yes_or_no)
store_id = models.ForeignKey(Store,default=1)
#property
def name(self):
return self.user.username
#property
def email(self):
return self.user.email
#property
def password(self):
return self.user.password
#property
def first_name(self):
return self.user.first_name
#property
def last_name(self):
return self.user.last_name
def __str__(self):
return self.user.username
In forms.py
class StaffForm(forms.ModelForm):
name = forms.CharField(max_length=100)
email= forms.EmailField(max_length=100, required=True)
password = forms.CharField(max_length=50)
store_id = forms.ModelChoiceField(queryset = Store.objects.all(),empty_label="--------") # select values ?
first_name = forms.CharField(required = True,max_length=100)
last_name = forms.CharField(required = True,max_length=100)
class Meta:
model = Staff
fields = ('gender','birthday','authorized','store_id')
widgets = {'authorized':forms.RadioSelect,
'gender':forms.RadioSelect,
'birthday':SelectDateWidget(years=range(date.today().year-50,date.today().year))
}
def save(self,*args,**kwargs):
Staff = super(StaffForm,self).save(commit=False)
user = User.objects.create(
username=self.cleaned_data['name'],
first_name=self.cleaned_data['first_name'],
last_name = self.cleaned_data['last_name'],
email= self.cleaned_data['email'])
user.set_password(self.cleaned_data['password'])
if self.cleaned_data['authorized']:
user.is_staff = True
Staff.user = user
Staff.save()
In views.py
#login_required(login_url='/dataInfo/login/')
def createstaff(request):
# if this is a POST request we need to process the form data
if request.method == 'POST':
# create a form instance and populate it with data from the request:
form = StaffForm(request.POST or None)
# check whether it's valid:
if form.is_valid():
# process the data in form.cleaned_data as required
form.save()
return HttpResponseRedirect('/dataInfo/staff_view/')
# if a GET (or any other method) we'll create a blank form
else:
form = StaffForm()
return render(request, 'dataInfo/create_staff.html', {'form': form})