form for simultaneously editing two django models with foreign key relationship

Question

I am trying to find a simple way to create a form that allows the editing of two models with foreign key relationship simultaneously.

After some research, it seems that Inline formsets come very close to what I want to do.

The django documentation offers this example:

from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)

class Book(models.Model):
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
    title = models.CharField(max_length=100)

And then,

>>> from django.forms import inlineformset_factory
>>> BookFormSet = inlineformset_factory(Author, Book, fields=('title',))
>>> author = Author.objects.get(name='Mike Royko')
>>> formset = BookFormSet(instance=author)

Let's suppose Author has a second field, city. Can I use the fields argument to add a city to the form?

If inline formsets are not the way to go, is there another way that generates this joint form?

After some more research, I found django model Form. Include fields from related models from 2009 which hints that inline form sets might not be the way to go.

I would be very much interested if there's a default solution with a different factory.

Hey, @cel I was wondering, did you find my answer helpful? – John Moutafis Feb 02 '18 at 11:52 — John Moutafis, Feb 02 '18 at 11:52
@JohnMoutafis, yes! sorry I forgot to upvote :) – cel Feb 04 '18 at 08:24 — cel, Feb 04 '18 at 08:24

score 3 · Accepted Answer · edited Nov 06 '19 at 10:40

Well, this is a bit different from the linked post because there the relationship is a OneToOne and not a ForeignKey.

There is no django factory (at least that I know of) to do what you want automatically. You can try the following instead:

Create a ModelForm for the depended table (Book in this case):

class BookForm(forms.ModelForm):
    class Meta:
        model = Book
        fields = ['name', 'city', 'other_field', ...]

Create an inline_formset for the depended table:

BookFormSet = inlineformset_factory(Author, Book, form=BookForm)

Use the formset in your view:

def my_view(request):
    if request.method == 'POST':
        formset = BookFormSet(request.POST, instance=request.user)
        if formset.is_valid():
            ...
            formset.save()
    else:
        formset = BookFormSet(instance=request.user)
    return render_to_response("template.html", {"formset": formset})

OR in a class based view: django class-based views with inline model-form or formset

Finally in the template (this part needs a bit of fumbling to get it right, but this is a general idea):

<form action="." method="post">
    {% csrf_token %}
    {{ formset }}
    {{ formset.management_form }}
    <input type="submit" value="Submit">
</form>

how does this render the Author profile? It would only show one form, being the books? — alias51, Aug 29 '19 at 16:28

form for simultaneously editing two django models with foreign key relationship

1 Answers1

Linked