Java programmers may be interested in this, from the website:
Mckoi SQL Database is an SQL (Structured Query Language) Database management system written for the JavaTM platform. Mckoi SQL Database is optimized to run as a client/server database server for multiple clients, however it can also be embedded in an application as a stand-alone database. It is highly multi-threaded and features an extendable object-oriented engine.
McKoi is released under the GNU General Public License and supports the SQL standard to a comparable level of other SQL database management systems available (see McKoi SQL Syntax). McKoi supports similar data-types to mySQL but with the addition of JAVA_OBJECT , allowing a serializable objects in Java to be stored.
I couldn't find any mention on if McKoi supports referential integrity which the default database engine in mSQL does not. Not really that big a deal if you design your appication to implement these features itself.
This will be the first thing I will be playing with in the holidays as it looks very useful!
