two good options for an embedded, transactional database that can be conveniently used in a non-free Python application: the ZODB and sqlite.
Related
Using the SQLObject Support package
codespeak.net · · Page
a nice tutorial on using sqlobject with Zope3.Yoohoo!!
Spyced: ORM design part 2: Jonathan's Python Blog
spyced.blogspot.com · · Page
Connecting databases to Python with SQLObject
www-128.ibm.com · · Page
Handling Form data with Formencode + SQLObject
groovie.org · · Page
Presentation on SQLObject & FormEncode
groovie.org · · Page
How To Love ZODB and Forget RDBMS
zope.org · · Page
tutorials on using ZODB in standalone mode