User profiles and object associations

2 comments

1. I don’t know Drupal, however, seems to me that what is “node” in drupal is “post type” in WordPress.

   By default WordPress has several post types: posts, pages, atthachments, menu items, revisions (these post types are often referred as “built-in”).

   You can register any number of custom post types, aka CPT.

   Post types, in database, differe one from another just for the ‘post_type’ column in posts table.

   However, the “behavior” they have can be very different, and depend on the post type registration arguments.

   So you can have post type hierachical and not hierachical, post type that need a specific user capability to be edited, post type ‘public’ and not public and so on.

   As example, menu items nad revisions are not public: the default UI is hidden and WordPress has a different UI fo them.

   In WordPress every post, regardless the type, has an author. (just like nodes have authors in Drupal, for what I can understand).

   Post to author relation is one-to-many (a post can have only one author and an author can have many posts). This relation, in database, is handled via a post_author field in the post table.

   That field refere to an ID in the users table: so the unique author for the post is an user: has a username, a passwrd, a profile, and so on.

   In you case, “Book” should be a post type, and if it’s good for you that book author is a real user, you can use link books and authors using the post author field.

   That will be easy to do because default post creation/editing UI has a field to set up the users, and also there are some default template tags that you can use (like the_author and related).

   In addition you can use the template hierarchy to easily customize the author archive (in WordPress an “archive” is web page that shows a set of posts that share a feature: a taxonomy archive is a page showing posts with same taxonomy, just like an author archive is a page showing posts of a specific author).

   If your authors are not real people, but is only a way to connect books, you may consider use a different approach, because if book authors are post authors (so users) they should have an email, an account and so on…

   Alternatives are, in fact, using another post type for authors, or using a taxonomy.

   Taxonomies are another type of “entity” in WordPress. Every taxonomy can have unlimited terms (just like avery post type can have unlimited posts). Categories and tags are the 2 default taxonomies, but you can register unlimited custom taxonomies.

   Regarding the way posts can be connected to other posts, in WordPress, out-of-the box, you have to way:

   1. One-to-Many relation of posts with same post type: this is the parent-child relationship that you can setup simply registring a post type as hierachical. Example is WordPress pages.
   2. Second type is a sort of “indirect” Many-to-Many relation using taxonomy. You can assign same taxonomy term to different posts (even of different post types) and the retrieve or show posts that share same term, “connecting” them. As example, you can create a taxonomy for every book author and assign the taxonomy to books, than using taxonomy archives to show posts.

   So if your book authors are not real users taxonomy can be the right choose.

   Now the WooCommerce “problem” (or better the problem you can have with WooCommerce). That plugin register a post type to handle products, the cpt name is ‘product’.

   If you register a custom post type fo books, than you can’t sell them with WooCommerce, because only ‘Products’ (post with post type ‘product’) can be selled out-of-the box using that plugin.

   I don’t know if there is any plugin that allow selling others custom post types. However an easy way to solve the problem can be using ‘Product’ post type for books and

   • register a custom taxonomy called ‘Product Type’ an create in it the term ‘Book’
   • a probably better alternative is create your own WooCommerce product type for Books. See this WPSE answer by @helgatheviking. WooCommerce product types are the way the plugin use to handle product with different features (simple, variable, downloadable, and so on).

   Regarding connect book products to books authors, if you use post author, then simply assign the right author and then when you need to show the link to author archive use the_author_link template tag. If you use a taxonomy then use get_term_link template tag to show then link to the related archive.

   There is an alternative I’ve not already mentioned. If book authors are not real users (so you don’t use pos author field) and you want create an author archive (a page that shows all authors) along with a “single view” of every author (e.g. a page with author biography, informations, photos…) probably you have to create another post type for authors.
   That can be a problem: as said before, out-of-the-box there isn’t in WordPress a system to directly connect post with different post types (in your case ‘product’ and ‘author’).

   A well known plugin, Posts2Posts can help to solve this problem, or you can handle that connection by yourself using a custom meta field (maybe ‘book_author_id') on product (or book) post type. In that case, the link to related author page can be shown in the loop (product archive or product single page) using get_permalink in combination with get_post_meta, something like:

   $author = get_post( get_post_meta( get_the_ID(), 'book_author_id', TRUE) );
   $title = apply_filters('the_title', $author->post_title);
   $link = get_permalink($author);
   echo '<a href="' . $link . '" title="' . $title. '">' . $title. '</a>';
   

   After that, in the single author template (according to template hierarchy it will be 'single-author.php' you can show the author information (post content) along to all all book for that author, using a custom WP_Query using ‘meta_query’ argument, something like:

   // single-author.php
   
   the_post();
   
   <h1>Author Name: <?php the_title() ?></h1>
   <h2>Author Info</h2>
   <div><?php the_content() ?></div>
   
   <h2>Books by <?php the_title() ?></h2>
   <?php
   $args = array(
     'post_type' => 'products',
     'meta_query' => array(
       'meta_key' => 'book_author_id',
       'meta_value' => get_the_ID()
      )
   );
   $books = new WP_Query( $args );
   if ( $books->have_posts() ) : while( $books->have_posts() ) : $books->the_post(); 
   ?>
   
   <div class="book">
     <h3><?php the_title() ?></h3>
     <p><?php the_excerpt() ?></p>
     <a href="<?php the_permalink() ?>">Details</a>
   </div>
   
   <?php endwhile; wp_reset_postdata(); else: ?> 
   <div>Sorry, <?php the_title() ?> has no books.</div>
   <?php endwif; ?>
   

   However, if book authors are real users (the should have an account on the site) I strongly recommend to use post author to connect books with book authors and if you need to some information for author archive you can use the author description field in user profile page and use a custom page template in combination with an WP_User_Query if you want ot show an archive of all book authors.

2. This is a very general question and so will be the answer – “Anyway you like”.

   AFAIK WordPress is less rigid platform then drupal and there is no one supported way to associate objects in the system, and wordpress is actually evolving all the time and offering new ways to do that.

   If we look only at what is concerned to be best practice at this point in time, the easiest part in you question is handling of products, they will be a custom post time which is related to a post in a similar way it would have been related to a node in drupal.

   Book authors are harder. In my world, users are only entities that may login to the system and I assume that book author will not be invited to login to your shop, therefor they are not users.
   What should they be? This will depend on other factors, should the be searchable, should you be able to group them, or will they just be used to group products. Depending on the exact need you might chose to also do then as CPT but you might want to do them as taxonomies.

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