Django get_or_create model function - django

Question

In one of my recent project, I created a website for users to submit their information in a multi-stage form, in each form I use get_or_create to see if the user submit information previously or not, for example, consider user education model as follows,
class UserEducation(models.Model):
user = models.ForeignKey(AUTH_USER_MODEL, on_delete=models.CASCADE)
university_name = models.CharField(max_length=100)
in the view, I have the following code,
def education_view(request):
if request.method == "POST":
uedu, created = UserEducation.objects.get_or_create(user=request.user)
uedu.university_name = request.POST['university_name']
uedu.save()
return HttpResponse("success")
I didn't set uploading for the submit button and the problem is some users have multiple education object!
Does anyone know why this happened and whats is wrong with get_or_create?

Answer 1

Insted you can use update_or_create
uedu, created = UserEducation.objects.update_or_create(
user=request.user,uedu.university_name = request.POST['university_name'],
defaults={'user': 'default_value'},
)

Answer 2

I think the reason is that, as every time you moved on to the next step, Django will think that you tell it to create a new object because, as every time you submit a form, a new Model will be created.
What you should do is to halt the process until everything is finished. Something like:
class Person(models.Model):
fn = models.CharField(max_length=40)
class Pet(models.Model):
owner = models.ForeignKey(Person)
name = models.CharField(max_length=40)
class PersonForm(forms.ModelForm):
class Meta:
model = Person
class PetForm(forms.ModelForm):
class Meta:
model = Pet
exclude = ('owner',)
#views
def step1(request):
initial={'fn': request.session.get('fn', None)}
form = PersonForm(request.POST or None, initial=initial)
if request.method == 'POST':
if form.is_valid():
request.session['fn'] = form.cleaned_data['fn']
return HttpResponseRedirect(reverse('step2'))
return render(request, 'step1.html', {'form': form})
def step2(request):
form = PetForm(request.POST or None)
if request.method == 'POST':
if form.is_valid():
pet = form.save(commit=False)
person = Person.objects.create(fn=request.session['fn'])
pet.owner = person
pet.save()
return HttpResponseRedirect(reverse('finished'))
return render(request, 'step2.html', {'form': form})
Reference

Answer 3

I find the following note in the documentation,
Warning
This method is atomic assuming that the database enforces uniqueness
of the keyword arguments (see unique or unique_together). If the
fields used in the keyword arguments do not have a uniqueness
constraint, concurrent calls to this method may result in multiple
rows with the same parameters being inserted.
the university does not have a unique constraint on the user foreign key and as the result, multiple objects will be saved in the concurrent calls.