I'm trying to setup a secure append-only database with PostgreSQL or MySQL. My idea for that is to generate a database where no admin/superuser accounts exists and only users with limited privileges can insert data to the database. The lack of superuser accounts should be no problem as the database will be setup completely from scratch if any admin changes need to be made.
My idea was to generate the database with an admin user (with an encrypted hash) and then immediately delete the admin user (or lock him out by setting the password to blank).
Is that a suitable approach?