Zope Related Links

The Zope Book for v2.7

This is a great reference if you plan on customizing Plone beyond skinning. You will need to understand Zope and its underlying architecture before creating applications that use among other things an external database.

Cataloging SQL Data and Almost Anything Else

This How-To describes specifically how to get SQL data into a ZCatalog for searching, but the principles here can be used to put just about anything into the catalog. Without this, if you decide to use an external database with Plone, your data will not be searchable using the Plone Search Tool.

Zope System Architecture

A good reference for Zope's underlying system architecture.