DuckDuckGo.com reports that Apache Derby is
.. a relational database management system developed by the Apache Software Foundation that can be embedded in Java programs and used for online transaction processing. It has a 2.6 MB disk-space footprint.
and directs the curious to this link
That's not really a Perl-related question. :/
Alex / talexb / Toronto
Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.