IntegrityError at /admin/flatpages/flatpage/add/

[dfcode]

In attempt to share users and sessions across multiple Django projects, I have created a database router for the session and auth models. This caused a hiccup for the admin site when I needed to generate a superuser in the remote database so I could login to /admin/. It seemed to work fine until I tried to make a change and the following error occured:

IntegrityError at /admin/flatpages/flatpage/add/
insert or update on table "django_admin_log" violates foreign key constraint "django_admin_log_user_id_fkey"
DETAIL: Key (user_id)=(2964) is not present in table "auth_user".

It seems that the logging system is not honoring my router for the 'auth' model.

[Karen Tracey]

There's not enough information here to evaluate where the problem is, nor if what you are trying to do is even possible given the current constraints of multi-db. One of those constraints is no ForeignKeys crossing databases (see ​http://docs.djangoproject.com/en/1.3/topics/db/multi-db/#cross-database-relations). The error is getting reported for an admin model (the admin log entry model: https://code.djangoproject.com/browser/django/tags/releases/1.3/django/contrib/admin/models.py#L13) that has a ForeignKey to the auth User model. Has your routing setup taken into account how to deal with non-auth models that may have ForeignKeys to auth-provided models such as User?

[lukazb@…]

I am experiencing similar error in the admin interface with Django 1.6.1. I have a custom user model and multiple database setup. It happens every time I try to perform a save action on any model. There are only two databases and no foreign-key relations crossing over.
Two unexpected factors:
1) missing key value is very high (148) and I currently have only 1 user on my development machine, so why 148? I might have deleted some accounts, but I doubt it was as many as 148...
2) relation target table is auth_user, while I do have a custom user model which is a separate table (user_client). Why does the admin enforce relation to the auth_user table (which is empty btw)?

[lukazb@…]

the error persists with single database setup. it seems the custom user model is the culprit.

[Claude Paroz]

It might be an issue with a incomplete migration to a custom user model. To debug that, we'd need the result of ./manage.py sqlall admin on one side and the real structure/constraints of your database regarding the django_admin_log table.

[lukazb@…]

that's exactly reason. the custom user model had been improperly registered with the admin interface. my bad :)