Topic Tag: Displaying post relationships

Problem: I would like to be able to get the ids of both related posts in a M2M relationship using the PHP Post Relationships API, when the intermediary post ID is known.

Solution: Use the toolset_get_related_posts API to retrieve related post information using the intermediary ID like this:

$book = toolset_get_related_posts(
    123,
    'book-library',
    'intermediary',
    1000000,0,
    array(),
    'post_id',
    'parent'
  );
// returns Array( [0] => 234 )
 
$library = toolset_get_related_posts(
    123,
    'book-library',
    'intermediary',
    1000000,0,
    array(),
    'post_id',
    'child'
  );
// returns Array( [0] => 345 )

Relevant Documentation:
https://toolset.com/documentation/customizing-sites-using-php/post-relationships-api/

Problem:

There is a one-to-many relationship between Author and Essay; Author is the parent post of Essay. The Author CPT has a field named Person Type. Person Type has a couple possible values: student, faculty, and alumni.

I am trying to use a View to display a list of Essay posts whose Authors are alumni.Is this possible?

Solution:

Unfortunately, there isn't such a built-in feature within Views plugin, Views is using WordPress class WP_Query to query the posts, if you are querying "Essay" posts, Views can only filter the view by custom fields of "Essay" posts, it can not filter by fields of other post type, this is a limitation of WordPress.

Currently, I suggest you use [wpv-conditional] shortcode to check field "Person Type" value of related "Author" post, if the value is "alumni", then display the "Essay" post.

Relevant Documentation:

https://toolset.com/documentation/user-guides/conditional-html-output-in-views/