Make slug as ID Number for custom post types

Question

I want to make the slug for each of my custom post types to be the post ID number. How do I do this? None of my posts accept post title, content, or anything else - they require different data which was easier to display as a meta box). To illustrate:

I have a CPT ('eduation'). When I submit the post into the database, it has an ID of, say, 15. When I visit mysite.com/edu/15 ('edu' being the post slug that I have set), I see the details from this post in my site.

I know I could simply change the permalinks, but I want those to stay as they are; I just want to change the ones for these custom post types. Sorry if the question is confusing. It probably is really simple to answer, but I really don't know what the answer is.

Answer 1

Here's a way how to change the slug:

add_action('wp_insert_post', 'change_slug');
function change_slug( $post_id ) {

       // Making sure this runs only when a 'eduation' post type is created
       $slug = 'eduation';
       if ( $slug != $_POST['post_type'] ) {
          return;
       }

       // `wp_update_post` calls `wp_insert_post`. Prevent infinite recursions!
       $post = get_post($post_id);
       if ($post->post_name == $post_id) return;


       wp_update_post( array(
        'ID' => $post_id,
        'post_name' => $post_id // slug
       ));

}