Currently, there is no portable way to determine the reason of an Exception.
E.g. if an exception occurs during saving, it could be due to a unique key violation.
It would be nice such a Violation would result in a special subclass of TorqueException, so the reason could be determined in a way portable across databasess
(Currently one can look at the root cause of the Torque exception and then e.g. form ysql check whether it's a MySQLIntegrityConstraintViolationException, but of course this is not portable across databases)