What Karl said.

Long Answer:

That being said, TurboGears does provide support for the SQLAlchemy SQL
toolkit / ORM.  If you use SQLAlchemy rather than SQLObject, you can
use the migrate package (http://erosson.com/migrate) for doing schema
evolution and migration.

The migrate package was a Google Summer of Code project that I mentored
and provides the ability to manage and version your database changes
over time, including creation/modification/removal of tables, columns,
indexes, and constraints in a database independent way.

The only other framework that provides something like this is Ruby on
Rails' ActiveRecord ORM in its "migrations" package, but it is highly
restrictive when it comes to what kinds of schemas are supported due
to ActiveRecord's strict adherence to the design pattern of the same
name.

--
Jonathan LaCour
http://cleverdevil.org