private bool NextRow ()
{
OdbcReturn ret = libodbc.SQLFetch (hstmt);
if (ret != OdbcReturn.Success)
currentRow = -1;
else
currentRow++;
// Clear cached values from last record
foreach (OdbcColumn col in cols) {
if (col != null)
col.Value = null;
}
return (ret == OdbcReturn.Success);
}