Opened 8 years ago

Closed 8 years ago

Last modified 4 years ago

#8097 closed Uncategorized (worksforme)

Many-to-many self-referential intermediates in admin: <Friendship> has more than 1 ForeignKey to <Person>

Reported by: Boo Owned by: nobody
Component: contrib.admin Version: master
Severity: Normal Keywords: ManyToManyField, admin
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no


This URL returns traceback:


Request Method: GET
Request URL:
Django Version: 1.0-alpha-SVN-8199
Python Version: 2.5.2
Installed Applications:
Installed Middleware:

File "/opt/local/lib/python2.5/site-packages/django/core/handlers/" in get_response
  87.                 response = callback(request, *callback_args, **callback_kwargs)
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in root
  156.                 return self.model_page(request, *url.split('/', 2))
File "/opt/local/lib/python2.5/site-packages/django/views/decorators/" in _wrapped_view_func
  44.         response = view_func(request, *args, **kwargs)
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in model_page
  173.         return admin_obj(request, rest_of_url)
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in __call__
  259.             return self.add_view(request)
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in add_view
  504.             for FormSet in self.get_formsets(request):
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in get_formsets
  340.             yield inline.get_formset(request, obj)
File "/opt/local/lib/python2.5/site-packages/django/contrib/admin/" in get_formset
  743.             extra=self.extra, max_num=self.max_num)
File "/opt/local/lib/python2.5/site-packages/django/forms/" in inlineformset_factory
  479.     fk = _get_foreign_key(parent_model, model, fk_name=fk_name)
File "/opt/local/lib/python2.5/site-packages/django/forms/" in _get_foreign_key
  464.             raise Exception("%s has more than 1 ForeignKey to %s" % (model, parent_model))

Exception Type: Exception at /admin/foo/person/add/
Exception Value: <class ''> has more than 1 ForeignKey to <class ''>

Please, see the testcase to reproduce this bug.

Attachments (1)

testcase.tar.gz (2.4 KB) - added by Boo 8 years ago.
TestCase to repeat the problem

Download all attachments as: .zip

Change History (4)

Changed 8 years ago by Boo

Attachment: testcase.tar.gz added

TestCase to repeat the problem

comment:1 Changed 8 years ago by MilosU

Needs documentation: unset
Needs tests: unset
Patch needs improvement: unset
Resolution: worksforme
Status: newclosed

There is no problem actually, you only need to define the fkey that admin app should use for the relation. If you have model like this (your testcase):

class Person(models.Model):

name = models.CharField(max_length=20)
friends = models.ManyToManyField('self', through='Friendship', related_name='friend_of', symmetrical=False)

def unicode(self):


class Friendship(models.Model):

first = models.ForeignKey(Person, related_name='rel_from_set')
second = models.ForeignKey(Person, related_name='rel_to_set')
date_friended = models.DateTimeField(auto_now_add=True)

def unicode(self):

return u'%s
%s' % (,

You need to specify fk_name attr on inline object:

class FriendshipInline(admin.TabularInline):

model = Friendship
fk_name = 'first'

Similarly could could edit the second side of the relation like this on a single page:
class SecondFriendshipInline(admin.TabularInline):

model = Friendship
fk_name = 'second'

Your PersonAdmin would be then like this:

class PersonAdmin(admin.ModelAdmin):

inlines = [FriendshipInline, SecondFriendshipInline], PersonAdmin)

This subtle config addon is however not mentioned currently in the docs, you need to go to the source.

comment:2 in reply to:  1 Changed 8 years ago by MilosU

Hmm.. Actually, this is already documented here:

I guess this was not there 5 hours ago..


comment:3 Changed 4 years ago by anonymous

Easy pickings: unset
Severity: Normal
Type: Uncategorized
UI/UX: unset

The documentation seems to have been moved from underneath Milos' link. Here's an updated link:

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