Import predefined data to database using YAML

I would need a way to import some data which I already have in the YAML
format to be written to the database. This is used especially to preload
database with some standard data like postal codes and different
for my objects.

How may I proceed to import the data to the DB? I also have some of the
available as XML so if it would be easier to do it with XML please
advise me
to do so!

Thank you for your help in advance!

Sven Clement