ZODB is an Object Oriented DB. A key advantage of ZODB is that you can time-travel (as long as you've not packed the DB and cleared old data). This collects some basic tips to get the history as well as the old state of that object.

ZODB related code snippets

# Get an object given its OID
from ZODB.utils import p64
obj = root._p_jar.get(p64(OID))

# Get the history of an object
history = obj._p_jar.get_history(obj._p_oid, 99)

# Get the old state of an object given its history
obj._p_jar.oldstate(obj, history[IDX]['tid'])