sql backend - guid

[marcus.wolschon at googlemail.com]

On Wed, 17 Jun 2009 08:27:54 -0400, Derek Atkins <warlord at MIT.EDU> wrote:
> Each object needs to have a stable GUID, and the SQL and XML need to
> remain equivalent.

Could you please explain that in more detail?
I thought the Database-backend was a replacement
for the XML-backend. Why would you still need the
XML-files?

Marcus