int n = 0;
do
{
String vtIdentifier = mtIdentifier + '.' + (++n);
vtRangeVar = idFactory.newIdentifier(IdentifierFactory.TABLE, vtIdentifier);
} while (qs.getTableExpression(vtRangeVar) != null);
ClassLoaderResolver clr = qs.getClassLoaderResolver();
QueryExpression qexpr = getBackingStoreQueryable().getExistsSubquery(qs, mapping, te, mtRangeVar);
ScalarExpression joinKeysExpr = getBackingStoreQueryable().joinKeysTo(qexpr,