[Zope] ZODB question: get older object versions without undo

I have two questons concerning ZODB: 1. Since ZODB does not overwrite objects on change one can get the older versions when undoing the changes. My question now: how can I access older versions of objects without undoing transactions? (I had a short glance at the ZODB classes, but found nothing) 2.Is it possible ( or will be ) to define ZODB objects for which updates are done by overwriting and not appending to the object database - That is an important issue for objects that are subject to frequent and simple changes. For example Webcounters or Advertising banners that count the clicks. Solutions to write these changes into external files (like FSCounter) are not more than emergency solutions for me. thanks phil