LiquiBase is a java based LGPL tool for managing database changes. If
you have used Ruby on Rail's Active Migration it is similar in concept,
although it tracks applied changes differently.

The most recent version of LiquiBase (1.3.2) has added Firebird support.

Major functionality includes:
- 34 Refactorings
- Extensibility to create custom refactorings
- update database to current version
- rollback last X changes to database
- rollback database changes to particular date/time
- rollback database to "tag"
- Stand-alone IDE and Eclipse plug-in
- "Contexts" for including/excluding change sets to execute
- Database diff report
- Database diff changelog generation
- Ability to create changelog to generate an existing database
- Database change documentation generation
- Ability to save SQL to be applied for approval by a DBA
- DBMS Check, user check, and SQL check preconditions
- Can split change log into multiple files for easier management
- Can be run via command line, Ant, Maven, Servlet container, or
Spring
- Support for 11 database systems

Visit the LiquiBase site for more information and for downloads:
http://www.liquibase.org

Nathan