muwed is a PostgreSQL based database for managing collections of mp3 or other music files, a few perl scripts to fill the database and a PHP web front end to access the database.
The PHP Accelerator is an easily installed PHP Zend engine extension that provides a PHP cache, and is capable of delivering a substantial acceleration of PHP scripts without requiring any script changes, loss of dynamic content, or other application compromises.
mediadbs aims to produce a flexible database system for tracking and searching for multiple forms of electronic media (eg mp3, divx, ogg) distributed on multiple servers in a local network.
Glom is a GUI that allows you to design MySQL table definitions and the relationships between them. It also allows you to edit and search the data in those tables.
protosquared is a "data server prototype". It supports several data sources, such as XML and SQL databases and the communication protocol is highly configurable too.
Postgresql AutoDoc is a utility which will run through PostgreSQL system tables and returns HTML, DOT, and 2 styles of XML which describes the database.