CODEWITHSUNDEEP
djangodjango-modelsdjango-formsdjango-views
JohnnyCash
JohnnyCash

Reputation: 1261

Django Overwrite form data saved

I've posted about this problem before, but I still haven't found a solution so I'm hoping I'll have better luck this time.

I have a form that takes inputted data by the user. In another page, I am creating the identical form that the user has populated (pre-filled with that information) for editing purposes. Users will come to this page to EDIT the information they have already put in. My problem is that it isn't overwriting the instance. 

def edit(request):

   a = request.session.get('a',  None)

   if a is None:
       raise Http404('a was not found')

   if request.method == 'POST':
       form = Name_Form(request.POST, instance=a)
       if form.is_valid():
           j = form.save( commit=False )
           j.save()
   else:
       form = Name_Form( instance = a )

For this form, I'm using "unique_together" for some of the values. I'm also calling on `{{ form.non_field_errors }} in the template.

What is happening is when I make changes in the editing view, if the fields changes involves those defined in "unique_together" then an error is returned telling me that the instance already exists. Otherwise it saves a new instance. It isn't OVERWRITING.

Note that the reason i am using unique_together is that I want to prevent users from initially inputting the same form twice (before the editing stage, in the initial inputting view).

Any ideas?

EDIT: note that "a" refers to a session that includes a drop down box of all the available instances. This carried forward will indicate which instance the user wants to edit. `

Upvotes: 0

Views: 1133

Answers (3)

ilvar
ilvar

Reputation: 5841

You should not save objects in the session. If you really need to use a session - save a PK there and retrieve object right before giving it to Form. But the better solution is to send it in GET or POST parameters or included in url. Sessions are unreliable, data inside it can be destroyed between user's requests.

And you can retrieve value from a session in a more pythonic way:

try:
    a = request.session['a']
except KeyError:
    raise Http404('a was not found')

Upvotes: 0

Valchris
Valchris

Reputation: 1481

Why not do a database lookup of the model your trying to save and pull the fields from the form to the model then save the model?

Upvotes: 1

dani herrera
dani herrera

Reputation: 51655

Instead to store model a in session you should store it on database. Then edit it:

def edit(request, pk):

   a = A.objects.get( pk = pk)
   ...

pk it the a identifier, you can send it to view via urls.py. I encourage to you to use POST/Redirect/GET pattern.

You can add a 'state' field on your model to control workflow (draft, valid)

Upvotes: 1

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