Thanks, I'll pick it up.
The first thing to ask yourself here is whether or not it makes sense to use a database. Certainly that makes sense if you need concurrent read and write access, but if you only need to write from one source at a time an XML file sounds more like what you need. It supports your need for infinite hierarchy, and if you work without a DTD it allows setting of any properties that you would like. If you don't like the general bloat of an XML file you can make use of a library like libxml2 (http://www.xmlsoft.org) which natively and transparently supports compressed XML files. If you're absolutely sold on the need that this be in a database, buy a copy of Joe Selko's _SQL for Smarties_. It covers these hierarchical structures in great detail. Even after implementing this kind of structure before I wouldn't try it again without consulting Selko's book. Clay Dowling
