Switching Django project from sqlite3 backend to postgresql failes when loading datadump

The problem is simply that you're getting the content types defined twice - once when you do syncdb, and once from the exported data you're trying to import. Since you may well have other items in your database that depend on the original content type definitions, I would recommend keeping those.

So, after running syncdb, do manage.py dbshell and in your database do TRUNCATE django_content_type; to remove all the newly-defined content types. Then you shouldn't get any conflicts - on that part of the process, in any case.

There is a big discussion about it on the Django ticket 7052. The right way now is to use the --natural parameter, example: ./manage.py dumpdata --natural --format=xml --indent=2 > fixture.xml

In order for --natural to work with your models, they must implement natural_key and get_by_natural_key, as described on the Django documentation regarding natural keys.

Having said that, you might still need to edit the data before importing it with ./manage.py loaddata. For instance, if your applications changed, syncdb will populate the table django_content_type and you might want to delete the respective entries from the xml-file before loading it.

This worked for me. You probably want to ensure the server is stopped so no new data is lost. Dump it:

$ python manage.py dumpdata --exclude auth.permission --exclude contenttypes --natural > db.json

Make sure your models don't have signals (e.g. post_save) or anything that creates models. If you do, comment it out momentarily.

Edit settings.py to point to the new database and set it up:

$ python manage.py syncdb$ python manage.py migrate

Load the data:

./manage.py loaddata db.json