Newbie: Data import question

[David Goodenough]

I have an existing Customer Management System (which as it happens is
Postgresql based), and I need to be able to import customer details into
GnuCash once they move from being prospects to being customers.  I would
want to keep the CMS as the master in general for this.

For some customers I also have billing generated from an external application
which I then need to import into GnuCash.

This is all in the planning stage at the moment, and I am trying out the new
2.3.1 version with its SQL support.  But I would expect that loading the data
directly into the DB is going to be the wrong way to do this.

What is the approved mechanism for doing this?  I can generate an XML form
of the data quite easily if that would do, I just need the schema.

David