#17863: Storing user and user profile in different databases?
-----------------------------------------------+--------------------
Reporter: Henning Kage <henning.kage@…> | Owner: nobody
Type: Bug | Status: new
Component: contrib.auth | Version: SVN
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 1
Easy pickings: 0 | UI/UX: 0
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I am not sure, if this is a possible bug or a wanted feature. I want to
outsource all tables from a Django application in a separate database.
This includes the user profile, that I want to be stored in the app's own
database. I am using the following minimal project, to reproduce the
traceback:
'''settings.py'''
{{{
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'default.db',
},
'app': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'app.db',
}
}
DATABASE_ROUTERS = ['app.router.Router']
INSTALLED_APPS = [
# ...
'app',
]
AUTH_PROFILE_MODULE = 'app.UserProfile'
}}}
'''app/models.py'''
{{{
#!python
from django.contrib.auth.models import User
from django.db import models
class UserProfile(models.Model):
user = models.ForeignKey(User)
}}}
'''app/router.py'''
{{{
#!python
# -*- coding: utf-8 -*-
class Router(object):
def db_for_read(self, model, **hints):
if model._meta.app_label == 'app':
return 'app'
return None
def db_for_write(self, model, **hints):
if model._meta.app_label == 'app':
return 'app'
return None
def allow_relation(self, obj1, obj2, **hints):
if (obj1._meta.app_label == 'app'
or obj2._meta.app_label == 'app'):
return True
return None
def allow_syncdb(self, db, model):
if db == 'app':
return model._meta.app_label == 'app'
elif model._meta.app_label == 'app':
return False
return None
}}}
'''app/tests.py'''
{{{
#!python
from django.contrib.auth.models import User
from django.test import TestCase
from app.models import UserProfile
class SimpleTest(TestCase):
def test_userprofile(self):
u = User()
u.save()
p = UserProfile()
p.user = u
p.save()
u.get_profile()
}}}
Although it is possible to specify a custom user profile class, Django
always assumes, that the user profile model is saved in the same database
Django stores the auth_user table. The unittest will result in the
following traceback by calling the user's profile with `User.get_profile`:
{{{
Traceback (most recent call last):
File "/Users/henningkage/Projekte/sandbox/userprofile/app/tests.py",
line 14, in test_userprofile
u.get_profile()
File
"/Users/henningkage/Python/django_multi_db/src/django/django/contrib/auth/models.py",
line 401, in get_profile
self._state.db).get(user__id__exact=self.id)
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/models/query.py",
line 361, in get
num = len(clone)
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/models/query.py",
line 85, in __len__
self._result_cache = list(self.iterator())
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/models/query.py",
line 291, in iterator
for row in compiler.results_iter():
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/models/sql/compiler.py",
line 763, in results_iter
for rows in self.execute_sql(MULTI):
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/models/sql/compiler.py",
line 818, in execute_sql
cursor.execute(sql, params)
File
"/Users/henningkage/Python/django_multi_db/src/django/django/db/backends/sqlite3/base.py",
line 337, in execute
return Database.Cursor.execute(self, query, params)
DatabaseError: no such table: app_userprofile
}}}
Does Django needs the user and user profile model in the same database as
foreign keys across multiple databases are not possible? My attached
(minmal) change will return a valid user profile model instance. The only
disadvantage to me is the fact, that the user profile has no real relation
to the user and will only return the user's id. This would be the normal
behaviour for relationships across multiple databases. But it would be
possible to store the user profile in a different database than Django's
internal tables. If this topic has already been discussed and I missed it,
sorry for the ticket.
--
Ticket URL: <https://code.djangoproject.com/ticket/17863>
Django <https://code.djangoproject.com/>
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