Thank you Jenda
I must read this carefully und try it. I did not know XML::Rules bevor. The good news - this module exists for ActivePerl.
The "real" huge xml file consists of many nested structures like in the example. They "dive" from the surface of simple data such as the "address" or the "boss name" (and the "unit_id").
I had hence an idea to make several csv files with id of the unit (here in example shown as unit name) and connect them in the database later. This eclectic (promiscuous? :-)) idea comes since my knowledge of perl is limited and I have to get the things run at the same time.