diff options
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ref/contrib/contenttypes.txt | 37 |
1 files changed, 13 insertions, 24 deletions
diff --git a/docs/ref/contrib/contenttypes.txt b/docs/ref/contrib/contenttypes.txt index f100864236..7860bbdeb2 100644 --- a/docs/ref/contrib/contenttypes.txt +++ b/docs/ref/contrib/contenttypes.txt @@ -400,6 +400,14 @@ from ``TaggedItem``:: >>> TaggedItem.objects.filter(bookmarks__url__contains='django') [<TaggedItem: django>, <TaggedItem: python>] +Of course, if you don't add the reverse relationship, you can do the +same types of lookups manually:: + + >>> b = Bookmark.objects.get(url='https://www.djangoproject.com/') + >>> bookmark_type = ContentType.objects.get_for_model(b) + >>> TaggedItem.objects.filter(content_type__pk=bookmark_type.id, object_id=b.id) + [<TaggedItem: django>, <TaggedItem: python>] + Just as :class:`~django.contrib.contenttypes.fields.GenericForeignKey` accepts the names of the content-type and object-ID fields as arguments, so too does @@ -411,30 +419,11 @@ referred to above used fields named ``content_type_fk`` and ``object_primary_key`` to create its generic foreign key, then a :class:`.GenericRelation` back to it would need to be defined like so:: - tags = GenericRelation(TaggedItem, - content_type_field='content_type_fk', - object_id_field='object_primary_key') - -Of course, if you don't add the reverse relationship, you can do the -same types of lookups manually:: - - >>> b = Bookmark.objects.get(url='https://www.djangoproject.com/') - >>> bookmark_type = ContentType.objects.get_for_model(b) - >>> TaggedItem.objects.filter(content_type__pk=bookmark_type.id, - ... object_id=b.id) - [<TaggedItem: django>, <TaggedItem: python>] - -Note that if the model in a -:class:`~django.contrib.contenttypes.fields.GenericRelation` uses a -non-default value for ``ct_field`` or ``fk_field`` in its -:class:`~django.contrib.contenttypes.fields.GenericForeignKey` (for example, if -you had a ``Comment`` model that uses ``ct_field="object_pk"``), -you'll need to set ``content_type_field`` and/or ``object_id_field`` in -the :class:`~django.contrib.contenttypes.fields.GenericRelation` to -match the ``ct_field`` and ``fk_field``, respectively, in the -:class:`~django.contrib.contenttypes.fields.GenericForeignKey`:: - - comments = fields.GenericRelation(Comment, object_id_field="object_pk") + tags = GenericRelation( + TaggedItem, + content_type_field='content_type_fk', + object_id_field='object_primary_key', + ) Note also, that if you delete an object that has a :class:`~django.contrib.contenttypes.fields.GenericRelation`, any objects |