I've updated the ZODB 3 UML model at: http://www.zope.org/Documentation/Models/ZODB The most significant change is that I've removed "temporary versions" and added "subtransactions": http://www.zope.org/Documentation/Models/ZODB/ZODB_Transaction_Management_Do... Jim -- Jim Fulton mailto:jim@digicool.com Python Powered! Technical Director (888) 344-4332 http://www.python.org Digital Creations http://www.digicool.com http://www.zope.org Under US Code Title 47, Sec.227(b)(1)(C), Sec.227(a)(2)(B) This email address may not be added to any commercial mail list with out my permission. Violation of my privacy with advertising or SPAM will result in a suit for a MINIMUM of $500 damages/incident, $1500 for repeats.