Changed exception handling.
Added a find before performing an update.
Did not pass Cascade.DELETE since the database performs a cascade delete.
Call back method to fetch CodeDescription objects from a database.
Removed obsolete import statement.
Updated examples. Added a @Version column.
Every table now has an update_count filed used for versioning.
Updated derby database ddl.
Added CodeDescriptionCallBack.
Added optional = false to the non optional columns.
