id,summary,reporter,owner,description,type,status,component,version,severity,resolution,keywords,cc,stage,has_patch,needs_docs,needs_tests,needs_better_patch,easy,ui_ux 13141,ModelForm can't update model like the way it is documented,CNBorn,nobody,"I want to update a model from a modelform, In a view that handling the POST request, the code is like the following: {{{ #If we already have the object , 'once_set' will be True, this_mapping will be this object if request.method == 'POST': if once_set == False: f = MAPPING_MODEL_Form(request.POST) if f.is_valid() == True: f.save() save_success = True else: print f.errors save_success = False else: f = MAPPING_MODEL_Form(request.POST, instance=this_mapping) if f.is_valid(): f.save() save_success = True else: print f.errors save_success = False }}} It goes well, but when I want to updated a existing model, instead of updating, it always creates a new model with all the new values from request.POST. I am using Django 1.2 Beta1, I tried with Django 1.1's method (without instance;this_mapping=f.save()) but it didn't work out either. Therefore I had to turn to this hack: {{{this_mapping.update(name=f.cleaned_data['name'], mail=f.cleaned_data['mail'], mobile=f.cleaned_data['mobile'])}}} Absolutly confirmed with the logic, object do exists and it do creates a new one instead of updating it.",,closed,Uncategorized,1.2-beta,,worksforme,modelform instance,,Unreviewed,0,0,0,0,0,0