Multiple formsets and when posting associating them with an instance

[David]

Hi

I don't know if this is a common question, but I couldn't find anything resembling my problem.

I have a page called "Case". On this page some basic information is added along with the creation of 1 or 2 clients (fixed) Client's are FK to the Case model. These are added using inlineformset factory.

On the subsequent page, and the one with the problem, I need to query my Client model to see how many clients are associated with the Case. That determines how many formsets I should show. ie. 1 for 1 client, or 2 for 2 clients.

I chose to use modelformset factory, instead of inline as I don't know how many clients exist.

Each formset is designed to associate family relatives to each client and are therefor FK'd to the Client. eg: Parent model contains FK to Client.

My very rudamentary code below achieves this, however my modelformset factories that I am using to generate the forms don't respect the "unique_together" constraint. I suspect this is because I am not passing an instance to the formset on post. But because for the sake of argument "Parent" instance may not exist and instead is being POST'd to create, I cannot specify an instance.

@login_required

def create_new_family(request, case_pk):

case = Case.objects.get(pk=case_pk)

clients = Client.objects.filter(case=case_pk)[:2]

formset = {}

for client in clients:

formset[client.pk] = {}

formset[client.pk] = {}

if request.method == 'POST':

for client in clients:

formset[client.pk]['parents'] = ParentsFormset(request.POST, prefix='parents_' + str(client.pk),)

formset[client.pk]['siblings'] = SiblingsFormset(request.POST, prefix='siblings_' + str(client.pk))

formset[client.pk]['children'] = ChildrenFormset(request.POST, prefix='children_' + str(client.pk))

formset[client.pk]['stepchildren'] = StepChildrenFormset(request.POST, prefix='stepchildren_' + str(client.pk))

err = 0

for client_id, fs_dict in formset.items():

if not all(form.is_valid() for fs_type, form in fs_dict.items()):

err = err + 1

if err == 0:

for client_id, fs_dict in formset.items(): # a is client_id ## b is formset dict

if all(form.is_valid() for fs_type, form in fs_dict.items()):

for idx, fs in fs_dict.items(): # at this point all fs are formset instances

if fs.is_valid():

instances = fs.save(commit=False)

for instance in instances:

instance.client = Client.objects.get(pk=client_id)

instance.save()

return HttpResponseRedirect(reverse('family-create', kwargs={'case_pk': case_pk}))

else:

for client in clients:

formset[client.pk]['parents'] = ParentsFormset(prefix='parents_' + str(client.pk),

queryset=Parent.objects.filter(client=client))

formset[client.pk]['siblings'] = SiblingsFormset(prefix='siblings_' + str(client.pk),

queryset=Sibling.objects.filter(client=client))

formset[client.pk]['children'] = ChildrenFormset(prefix='children_' + str(client.pk),

queryset=Children.objects.filter(client=client))

formset[client.pk]['stepchildren'] = StepChildrenFormset(prefix='stepchildren_' + str(client.pk),

queryset=StepChildren.objects.filter(client=client))

return render(request, 'clients/client_form.html', {

'formsets': formset,

'clients': clients,

'case': case,

'breadcrumbs': 'Family & Dependants'

})

I appreciate this might be difficult to comprehend, as it is for me to explain.

Any help would be much appreciated.

Thank you 

[David]

Changing all modelformset factories to inlineformsets and then specifying an instance on both the post and get methods resolved this issue.