I am working on a simple project built on top of Django web framework. I have a user profile model that had 3 char fields that needed to be update from null=True to null=False When I run python manage.py migrate on the django app I get the following error django.db.utils.OperationalError: cannot ALTER TABLE "accounts_profile" because it has pending trigger events To fix this I run the PostgreSQL shell (psql) to update and set the changed fields. The SQL command for the fix is: db=# update accounts_profile set non_nullable_field = '' where non_nullable_field is null; I run the same command for the other two different fields. Follow me on twitter @bmwasaru