MySQL - The world's most popular open source database
SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Figure - Propellerhead creates world-class software products and services that inspire music makers and provide the foundation for a worldwide creative musical community.
SQLite - SQLite Home Page
keezy - A colorful soundboard. Play with music.