protected function dropIndexCommand($command, $type, $index)
    {
        $columns = array();

        // If the given "index" is actually an array of columns, the developer means
        // to drop an index merely by specifying the columns involved without the
        // conventional name, so we will build the index name from the columns.
        if (is_array($index)) {
            $columns = $index;

            $index = $this->createIndexName($type, $columns);
        }

        return $this->indexCommand($command, $columns, $index);
    }