Early in the development of WordPress 3.0, we had a preliminary discussion on changing the WordPress database class (wpdb) so that it could be inherited by plugins implementing a custom database class. We had a longer discussion on the subject while together at WordCamp San Francisco. As a result, there was a small change to WordPress 3.0 which allows the wpdb class to be inherited.
I’ve been working on switching SharDB over to inherit wpdb and finished up on a Development Version last night. I’m working with WordPress 3.0.1, but the dev version should work with WP 3.0 through to WP trunk. By taking advantage of inheritance, I was able to eliminate over 50% of the code in the SharDB custom DB class. All of the red in the Changeset is removed code.