EPRs can be accessed multiple times. This leads to a need to identify the semantics of the service with respect to 
multiple calls...
The problem is that not all database drivers support scrollable/reusable ResultSets - so only one client could retrieve 
the results of a given query.
A solution to this is to keep a copy of the results - but this introduces a memory problem. A more sophisticated 
approach would be to have a reusability property
which would force a copy to be made of the results to be made and/or a memory threshold property beyond which the 
associated EPR would be marked as not being re-usable.
This is a data service semantics issue.
The easiest solution for now, as coded in the DAISWSServer tech preview, is for ResultSets not to be kept in memory and 
only be re-usable if supported by the database driver..