Anyway, is there a way to add ones own table that ultimately provides the appropriate callbacks to ones own code?
If I understand your question correctly, in Derby we call these "Table Functions", and they have been added to Derby recently: https://issues.apache.org/jira/browse/DERBY-716
This feature will be part of Derby 10.4, which progress you can follow here: http://wiki.apache.org/db-derby/DerbyTenFourRelease We'd love to have some feedback about how well this feature works for you, so please give it a try and let us know! thanks, bryan