Django: object needs to have a value for field "..." before this many-to-many relationship can be used - sql

Question

I experience a strange error with Django 1.5:
I have defined a model like below:
class Company(models.Model):
user = models.OnetoOneField(User)
agreed_to_terms = models.NullBooleanField(default=False)
address = models.CharField(_('Complete Address'),
max_length = 255, null = True, blank = True)
winning_bid = models.ForeignKey('Bid',
related_name='winning_bid',
blank = True, null = True)
bid_list = models.ManyToManyField('Bid',
related_name='bids',
blank = True, null = True)
...
class Bid(models.Model):
user = models.ForeignKey(User, null = True, blank = True)
description = models.TextField(_('Description'),
blank = True, null = True,)
volume = models.DecimalField(max_digits=7, decimal_places=3,
null=True, blank=True,)
...
# all other attributes are of the Boolean, CharField or DecimalField type. No Foreignkeys, nor ManytoManyFields.
When I try to file the form with the initial data through the Django admin, I get the following error:
Exception Value:
"" needs to have a value for field "company" before this many-to-many relationship can be used.
Please see the traceback below.
The error message does not make very much sense to me. The only m2m relationship is bid_list, which is null = True and was null at the time of saving.
Is there something new in Django 1.5, which I have not discovered while reading the changelog (this is my first project in Django 1.5)?
Interestingly, when I save an object in the Django shell, I do not get an error message, but the object does not get saved without any error message.
In [1]: user = User.objects.get(username='admin')
In [2]: new_company = Company()
In [3]: new_company.user = user
In [4]: new_company.save() Out[4]: <Company: Company object>
In [5]: foo = Company.objects.all()
Out[5]: []
When I try to trace the SQL statements with the debug toolbar, I can only see SQL SELECT statements, no INSERT requests.
What is the explanation for this strange behaviour?
Traceback:
Request Method: POST
Request URL: /admin/company/company/add/
Django Version: 1.5.1
Python Version: 2.7.1
Installed Applications:
('django.contrib.admin',
'django.contrib.admindocs',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.gis',
'django.contrib.humanize',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.admin',
'django.contrib.admindocs',
'crispy_forms',
'django_extensions',
'easy_thumbnails',
'registration',
'south',
'company',
'bid',
'debug_toolbar')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'debug_toolbar.middleware.DebugToolbarMiddleware')
Traceback:
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
115. response = callback(request, *callback_args, **callback_kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
372. return self.admin_site.admin_view(view)(*args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
91. response = view_func(request, *args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
89. response = view_func(request, *args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
202. return view(request, *args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
25. return bound_func(*args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
91. response = view_func(request, *args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
21. return func(self, *args2, **kwargs2)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/db/transaction.py" in inner
223. return func(*args, **kwargs)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view
1008. self.save_related(request, form, formsets, False)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/contrib/admin/options.py" in save_related
762. form.save_m2m()
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/forms/models.py" in save_m2m
84. f.save_form_data(instance, cleaned_data[f.name])
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/db/models/fields/related.py" in save_form_data
1336. setattr(instance, self.attname, data)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/db/models/fields/related.py" in __set__
910. manager = self.__get__(instance)
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/db/models/fields/related.py" in __get__
897. through=self.field.rel.through,
File "/Users/neurix/Development/virtual/lib/python2.7/site-packages/django/db/models/fields/related.py" in __init__
586. (instance, source_field_name))
Exception Type: ValueError at /admin/company/company/add/
Exception Value: "<Company: Company object>" needs to have a value for field "company" before this many-to-many relationship can be used.
settings.py
import os, os.path, sys
DEBUG = True
TEMPLATE_DEBUG = DEBUG
# Setting up folders
abspath = lambda *p: os.path.abspath(os.path.join(*p))
PROJECT_ROOT = os.path.abspath(os.path.dirname(__file__))
TASK2_MODULE_PATH = abspath(PROJECT_ROOT, 'apps/')
sys.path.insert(0, TASK2_MODULE_PATH)
# Loading passwords
try:
from settings_pwd import *
except ImportError:
pass
AUTH_PROFILE_MODULE = 'profile.UserProfile'
#ALLOWED_HOSTS = [''] # not needed for DEBUG = True
TIME_ZONE = 'Europe/London'
LANGUAGE_CODE = 'en-uk'
LANGUAGES = [
("en", u"English"),
]
SITE_ID = 1
USE_I18N = True
USE_L10N = True
USE_TZ = True
if DEBUG:
MEDIA_ROOT = os.path.join(PROJECT_ROOT, "site_media", "media")
else:
MEDIA_ROOT = "folder_to_upload_files"
if DEBUG:
MEDIA_URL = "/media/"
else:
MEDIA_URL = "/media/uploads/"
if DEBUG:
STATIC_ROOT = os.path.join(PROJECT_ROOT, "site_media","static")
else:
STATIC_ROOT = "folder_to_static_files"
STATIC_URL = '/static/'
STATICFILES_DIRS = (
os.path.join(PROJECT_ROOT, "assets"),
)
STATICFILES_FINDERS = (
'django.contrib.staticfiles.finders.FileSystemFinder',
'django.contrib.staticfiles.finders.AppDirectoriesFinder',
)
SECRET_KEY = '...'
TEMPLATE_LOADERS = (
'django.template.loaders.filesystem.Loader',
'django.template.loaders.app_directories.Loader',)
MIDDLEWARE_CLASSES = (
'django.middleware.common.CommonMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',)
ROOT_URLCONF = 'task2.urls'
WSGI_APPLICATION = 'task2.wsgi.application'
TEMPLATE_DIRS = (
os.path.join(PROJECT_ROOT, "templates"),
os.path.join(PROJECT_ROOT, "templates/pages"),)
INSTALLED_APPS = (
# Django apps
'django.contrib.admin',
'django.contrib.admindocs',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.gis',
'django.contrib.humanize',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.admin',
'django.contrib.admindocs',
# third party apps
'crispy_forms',
'django_extensions',
'easy_thumbnails',
'registration',
'south',
# task2 apps
'profile',
'company',
)
AUTHENTICATION_BACKENDS = (
'django.contrib.auth.backends.ModelBackend',
)
log = DEBUG
if log:
LOGGING = {
'version': 1,
'disable_existing_loggers': True,
'formatters': {
'simple': {
'format': '%(levelname)s %(message)s',
},
},
'handlers': {
'console':{
'level':'DEBUG',
'class':'logging.StreamHandler',
'formatter': 'simple'
},
},
'loggers': {
'django': {
'handlers': ['console'],
'level': 'DEBUG',
},
}
}
####################
# THIRD PARTY SETUPS
# For Crispy Forms
CRISPY_FAIL_SILENTLY = not DEBUG
CRISPY_TEMPLATE_PACK = 'bootstrap'
## For Django Registration
ACCOUNT_ACTIVATION_DAYS = 7
# for Django testing to avoid conflicts with South migrations
SOUTH_TESTS_MIGRATE = False
# Debug_toolbar settings
if DEBUG:
INTERNAL_IPS = ('127.0.0.1',)
MIDDLEWARE_CLASSES += (
'debug_toolbar.middleware.DebugToolbarMiddleware',
)
INSTALLED_APPS += (
'debug_toolbar',
)
DEBUG_TOOLBAR_PANELS = (
'debug_toolbar.panels.version.VersionDebugPanel',
'debug_toolbar.panels.timer.TimerDebugPanel',
'debug_toolbar.panels.settings_vars.SettingsVarsDebugPanel',
'debug_toolbar.panels.headers.HeaderDebugPanel',
#'debug_toolbar.panels.profiling.ProfilingDebugPanel',
'debug_toolbar.panels.request_vars.RequestVarsDebugPanel',
'debug_toolbar.panels.sql.SQLDebugPanel',
'debug_toolbar.panels.template.TemplateDebugPanel',
'debug_toolbar.panels.cache.CacheDebugPanel',
'debug_toolbar.panels.signals.SignalDebugPanel',
'debug_toolbar.panels.logger.LoggingPanel',
)
DEBUG_TOOLBAR_CONFIG = {
'INTERCEPT_REDIRECTS': False,
}
# Easy_Thumbnail setup
THUMBNAIL_ALIASES = {
'': {
'thumbnail': {'size': (50, 50), 'crop': True},
},
}

Answer 1

The problem has to do with how you use your views.
I think you are using:
instance.add(many_to_many_instance)
before you have an instance id.
so first save your model:
instance.save()
instance.add(many_to_many_instance)

Answer 2

You are using custom user model AUTH_PROFILE_MODULE = 'profile.UserProfile', but in code I suppose you use native django user.
I suppose your models should be like
class Company(models.Model):
user = models.OnetoOneField('profile.UserProfile')
...
read more https://docs.djangoproject.com/en/1.5/ref/contrib/auth/#django.contrib.auth.models.User.get_profile