This page is going to be a collection of common issues Django MongoDB Engine users faced. Please help grow this collection – tell us about your troubles!
AutoField (default primary key) values must be strings representing an ObjectId on MongoDB (got u'1' instead). Please make sure your SITE_ID contains a valid ObjectId string.
This means that your SITE_ID setting (What’s SITE_ID?!) is incorrect – it is set to “1” but the site object that has automatically been created has an ObjectId primary key.
If you add 'django_mongodb_engine' to your list of INSTALLED_APPS, you can use the tellsiteid command to get the default site’s ObjectId and update your SITE_ID setting accordingly:
$ ./manage.py tellsiteid
The default site's ID is u'deafbeefdeadbeef00000000'. To use the sites framework, add this line to settings.py:
SITE_ID=u'deafbeefdeadbeef00000000'
DatabaseError at /admin/auth/user/deafbeefdeadbeef00000000/
[...] This query is not supported by the database.
This happens because Django tries to execute JOINs in order to display a list of groups/permissions in the user edit form.
To workaround this problem, add 'djangotoolbox' to your INSTALLED_APPS which makes the Django admin skip the groups and permissions widgets.
You can simply use Django’s query logging system. An example configuration can be found here.