Revision 335

-Replaced the "sample" code with actual calls into the database code.  This
 would be very close to finished code, except that it suffers from a bug
 that has so far proved intractable to Sam and myself.  An email will be
 forthcoming detailing the bug.  Quite likely, the bug is not specifically
 in this file, and in the best case this file won't need to be changed much
 for a long time, unless I decide to change the interface for style reasons.