Import only streets and cities with osmosis

Hello, I managed to download and extract an osm-file into a mysql- or postgresql-database, like:

osmosis --read-xml myfile.osm --write-apidb dbType=“mysql” host=“localhost” database=“osm” user=“osm”

This works fine. What I now need is a way to get only cities and their streets into the database and query them. So how do I limit the data passed from the osm-file to the database to cities and streets? I don’t need any additional data like information to render a map.