How to work with many tables related to each other? about codeigniter-base-model HOT 1 OPEN

                $this->load->model('author_model', 'author');
        $this->load->model('author_book_model', 'author_book');

        // We want to get all the the books from author with ID = 1
        $author_id = 1;
        $author_obj = $this->author->get($author_id);

        $book_list = $this->author_book->with('book')->get_many_by('author_id', $author_id);

        echo "<h1>Books for the author '" . $author_obj->name . "'</h1>";
        echo "<ul>";
        foreach ($book_list as $book_single)
        {
            echo "<li>" . $book_single->book->name . "</li>";
        }
        echo "</ul>";