public function getHandle()
    {
        $ownerClass = get_class($this->owner);
        $ownerTable = $ownerClass::tableName();
        if (!isset(self::$_handle[$ownerTable])) {
            self::$_handle[$ownerTable] = [];

            $ownerClass = get_class($this->owner);
            $schema = $ownerClass::getTableSchema();

            foreach ($schema->columns as $column) {
                switch ($column->dbType) {
                    case 'date':
                        self::$_handle[$ownerTable][$column->name] = 'date';
                    break;
                    case 'time';
                        self::$_handle[$ownerTable][$column->name] = 'time';
                    break;
                    case 'datetime':
                        self::$_handle[$ownerTable][$column->name] = 'datetime';
                    break;
                }
            }
        }

        return self::$_handle[$ownerTable];
    }