ezSQL is an open source PHP database class that I wrote a while back. It’s used on over 100k websites and is the backbone of many open source projects such as WordPress. The class makes it ridiculously easy to use mySQL, Oracle8, SQLite (PHP), within your PHP script.
QCubed is a PHP framework for rapid web development. Building on top of jQuery, with OOP at its core, QCubed provides a powerful solution for building database-driven Web 2.0 applications.