stdin

stdin

-- accounts/models.py

class Member(models.Model):

    class Meta:
        abstract = True

    ...

    user = models.OneToOneField(User)

class Professional(Member):

    ...

    announces = GenericRelation('services.Announce',
                                verbose_name=_("annonces"),
                                content_type_field='announcer_type',
                                object_id_field='announcer_id',
                                related_query_name='professionals')

-- services/models.py

class Announce(models.Model):

    class Meta:
        abstract = True

    ...

    announcer_type = models.ForeignKey(ContentType)
    announcer_id = models.PositiveIntegerField()
    announcer = GenericForeignKey('announcer_type', 'announcer_id')

class Service(Announce):

    ...

class Job(Announce):

    ...

-- manage.py shell

Python 3.3.6 (default, Dec 10 2014, 19:08:56) 
[GCC 4.8.3] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from accounts.models import *
>>> Professional.objects.get(pk=1).delete()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/home/tony/.virtualenvs/aladompy/lib/python3.3/site-packages/django/db/models/query.py", line 536, in delete
    collector.collect(del_query)
  File "/home/tony/.virtualenvs/aladompy/lib/python3.3/site-packages/django/db/models/deletion.py", line 233, in collect
    sub_objs = field.bulk_related_objects(new_objs, self.using)
  File "/home/tony/.virtualenvs/aladompy/lib/python3.3/site-packages/django/contrib/contenttypes/fields.py", line 379, in bulk_related_objects
    return self.rel.to._base_manager.db_manager(using).filter(**{
AttributeError: 'str' object has no attribute '_base_manager'