title: Update 1 or many fields in django model without if else condition statement
body: <p>I currently have the following code:</p>
  
  <p>HTTP/POST</p>
  
  <pre><code>------WebKitFormBoundary2s9CNLxw7qrgzD94
  Content-Disposition: form-data; name="first_name"
  
  Mike
  </code></pre>
  
  <p>forms.py</p>
  
  <pre><code>class TenantUpdateForm(ModelForm):
      class Meta:
          model = Tenant
          fields = ["first_name", "last_name", "email", "birthday", "stars", "company",
                "position", "client_type", "phone", "identification", "comments"]
  </code></pre>
  
  <p>views.py</p>
  
  <pre><code>@csrf_exempt
  @jwt_authentication
  @require_http_methods(["POST"])
  def update_tenant(request, unique_key):
  
      instance = get_object_or_404(Tenant, unique_key=unique_key)
      form = TenantUpdateForm(request.POST, instance=instance)
  
      if form.is_valid():
          form.save()
          payload = {"status": True,
                  "description": "Tenant fields updated."}
  
          return HttpResponse(json.dumps(payload, indent=2, cls=json_encoder),
                              content_type='application/json',
                              status=200)
      else:
          payload = {"status": False,
                  "description": "Form is invalid.",
                  "form": form.errors.as_json()}
  
          return HttpResponse(json.dumps(payload, indent=2, cls=json_encoder),
                              content_type='application/json',
                              status=404)
  </code></pre>
  
  <p>So far everything works fine. But When I try to update just a single field it it changes the field but all the other fields go blank.</p>