Firebird is a relational database offering many ANSI SQL-99 features
that runs on Linux, Windows, and a variety of Unix platforms. Firebird
offers excellent concurrency, high performance, and powerful language
support for stored procedures and triggers. It has been used in
production systems, under a variety of names since 1981.
Firebird is completely free of any registration, licensing or deployment
fees. It may be deployed freely for use with any third-party software,
whether commercial or not.
WWW: http://sourceforge.net/projects/firebird/
WWW: http://www.firebirdsql.org/