protected function getKeys($table,$table2=null) {
		$pdo = $this->adapter->getDatabase()->getPDO();
		$keys = $pdo->cubrid_schema(PDO::CUBRID_SCH_EXPORTED_KEYS,$table);//print_r($keys);
		if ($table2) $keys = array_merge($keys, $pdo->cubrid_schema(PDO::CUBRID_SCH_IMPORTED_KEYS,$table2) );//print_r($keys);
		
		return $keys;
	}