[Zope] Database indexing using Z Catalogs

Hello, I am not able to find a way to index and external database say PostgreSQL using Z Catalogs and search the contents. Can anybody help me in this. I couldn't find a complete documentation in the zope site. It will be helpfull to me if somebody can explain to me using an example. Regards, Honey __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/