libgnodbify is a library that allows you to create GObjects from database tuples. It currently only works if you're using a PostgreSQL database; but in theory it should be possible to adapt the library to another DBMS.
Its features include:
However, the caching (and, thus, the asynchronous notification) isn't working very well yet. The objectization bits are.
It's in a pre-pre-pre-alpha state right now, but it works for me in this one particular project where I need it for work. YMMV. Also, read the TODO file if you're going to use it :)