public function AddFieldMap($fm)
	{
		$tablealias = $fm->TableName;
		if (!array_key_exists($tablealias, $this->Tables)) $this->Tables[$tablealias] = $fm->TableName;
		
		// debugging sequence of loading tables
		// print "<div>QueryBuilder->AddFieldMap:" . $tablealias . "-&gt;" . $fm->ColumnName . "</div>";
		
		$this->Columns[$tablealias ."-". $fm->ColumnName] = $fm->FieldType == FM_CALCULATION 
			? $fm->ColumnName 
			: "`" . $tablealias . "`.`" . $fm->ColumnName . "` as `" . $fm->ColumnName . "___" . $fm->TableName . "___" . $this->_counter++ . "`";
	}