python - django model instance edit -

i have 3 models set follows:

#models.py class room(models.model):     room_number = models.charfield(max_length=20, primary_key=true, null=false, blank=false)     isolation_status = models.booleanfield()   class treatment(models.model):     room_number = models.foreignkey(room, primary_key=true)     treated = models.booleanfield()  class isolation(models.model):     room_number = models.foreignkey(room, primary_key=true) 

what need when create new treatment object set room.isolation_status field false.

#views.py class addtxview(formview):     template_name = 'addtx.html'     form_class = txform     success_url = '/rooms/addtx/'  def update_iso(self, form):     instance = room.objects.get(room_number=room_number)     instance.isolation_status = false  def form_valid(self, form):     save_it = form.save(commit=false)     save_it.save()     return super(addtxview, self).form_valid(form)  #forms.py class txform(forms.modelform):     class meta:         model = treatment 

when should call update_iso function? after save()? should using class-based view

you set in model. whenever save treatment, check if new. if is, set isolation_status of room_number false.

#models.py class room(models.model):     room_number = models.charfield(max_length=20, primary_key=true, null=false, blank=false)     isolation_status = models.booleanfield()   class treatment(models.model):     room_number = models.foreignkey(room, primary_key=true)     treated = models.booleanfield()       def save(self, *args, **kwargs):         is_new = false         if self.pk none:             is_new = true         super(treatment,self).save(*args, **kwargs)         if is_new:             self.room_number.isolation_status = false             self.room_number.save()  class isolation(models.model):     room_number = models.foreignkey(room, primary_key=true) 

by doing work whenever add treatment (be in views or in admin).