django-nonrel with existing database

[arambadk]

Posting my question from stack overflow - http://stackoverflow.com/questions/31442632/django-nonrel-with-existing-legacy-database.

Sorry about filing an issue but I tried to attach the label "question" but was not successful in doing so. Please point me in the right direction if this is against community guidelines.

We have a large existing database and I am using django-nonrel to write an app on it. As far as possible I want to avoid using the pymongo interface to talk to the database.

I used the meta tag db_table to point to the existing collection and executed syncdb without any issues. I can see the collection in the admin view and .objects.all.count() returns the expected value but all the entries are none.

When I try to open an entry from admin view to edit/view it I get error -

AutoField (default primary key) values must be strings representing an ObjectID on MongoDB (got u'' instead)
When I googled I found this solution http://django-mongodb-engine.readthedocs.org/en/latest/troubleshooting.html but this doesnt look like the site ID issue as the value of _id from my mongo database.

Any pointers will be really helpful as replicating the data is not an option.

Thanks Aditya