Axiom is an object database, or alternatively, an object-relational mapper.

Its primary goal is to provide an object-oriented layer with what we consider 
to be the key aspects of OO, i.e. polymorphism and message dispatch, without 
hindering the power of an RDBMS. It is designed to "feel pythonic", without 
encouraging the typical ORM behavior such as potato programming.

Axiom provides a full interface to the database, which strongly suggests that 
you do not write any SQL of your own. Metaprogramming is difficult and 
dangerous (as many, many SQL injection attacks amply demonstrate). Writing 
your own SQL is still possible, however, and Axiom does have several methods 
which return fragments of generated schema if you wish to use them in your own 
queries. 

WWW: http://divmod.org/trac/wiki/DivmodAxiom