I have been given a hint to try out the inline formset as a solution to a problem. Just experimenting with it in a sandbox project. I am trying to replicate the exact same example as in the Django documentation and it fails. :(
Models:
TITLE_CHOICES = (
('MR', 'Mr.'),
('MRS', 'Mrs.'),
('MS', 'Ms.'),
)
class Author(models.Model):
name = models.CharField(max_length=100)
title = models.CharField(max_length=3, choices=TITLE_CHOICES)
birth_date = models.DateField(blank=True, null=True)
def __unicode__(self):
return self.name
class Book(models.Model):
name = models.CharField(max_length=100)
authors = models.ManyToManyField(Author)**
View:
def manage_books(request, author_id):
author = Author.objects.get(pk=author_id)
BookInlineFormSet = inlineformset_factory(Author, Book)
if request.method == "POST":
formset = BookInlineFormSet(request.POST, request.FILES, instance=author)
if formset.is_valid():
formset.save()
# Do something. Should generally end with a redirect. For example:
return HttpResponseRedirect(author.get_absolute_url())
else:
formset = BookInlineFormSet(instance=author)
return render_to_response("manage_books.html", { "formset": formset, })
In the admin screen I have successfully created an Author1
and Author2
.
Book1
and Book1b
are assigned to Author1
Book2
to Author2
.
When I try it I get a <class 'Sandbox_App.models.Book'> has no ForeignKey to <class 'Sandbox_App.models.Author'>
Traceback:
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/test/1
Django Version: 1.4.1
Python Version: 2.7.3
Installed Applications:
('django.contrib.auth',a
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'Sandbox_App',
'django.contrib.admin')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.locale.LocaleMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware')
Traceback:
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response
111. response = callback(request, *callback_args, **callback_kwargs)
File "/home/houman/projects/Sandbox/Sandbox_App/views.py" in manage_books
58. BookInlineFormSet = inlineformset_factory(Author, Book)
File "/usr/local/lib/python2.7/dist-packages/django/forms/models.py" in inlineformset_factory
817. fk = _get_foreign_key(parent_model, model, fk_name=fk_name)
File "/usr/local/lib/python2.7/dist-packages/django/forms/models.py" in _get_foreign_key
800. raise Exception("%s has no ForeignKey to %s" % (model, parent_model))
Exception Type: Exception at /test/1
Exception Value: <class 'Sandbox_App.models.Book'> has no ForeignKey to <class 'Sandbox_App.models.Author'>
Why is this not working?
Many Thanks
Like the error message states, Book should have a Foreignkey to Author. You are using a ManyToManyRelation.
authors = models.ManyToManyField(Author)
I tested the example from the docs in the shell and it works.
Also look here: Django inlineformset_factory and ManyToMany fields