1. Relationships Between
Custom Post Types
Randy Hoyt

2. @randyhoyt #orlandowordcamp
About Me
Randy Hoyt randyhoyt.com
@randyhoyt
Presentation randyhoyt.com/wcorlando

3. @randyhoyt #orlandowordcamp
Custom Post Types?
Posts Pages

4. @randyhoyt #orlandowordcamp
Event Calendar
Posts Pages Events

5. @randyhoyt #orlandowordcamp
Restaurant Chain
Posts Pages Locations

8. @randyhoyt #orlandowordcamp
University Course
Posts Pages Assignments

11. @randyhoyt #orlandowordcamp
wp_posts
ID post_type post_title
1 post Hello, world!
2 page Sample Page
231 rrh_assignment Final Exam

12. @randyhoyt #orlandowordcamp
wp_posts
ID post_type post_title
1 post Hello, world!
2 page Sample Page
231 rrh_assignment Final Exam
Structured Data in WordPress
http://randyhoyt.com/wcto

13. @randyhoyt #orlandowordcamp
Shopping Center
Stores
Posts Pages
Sales Jobs

14. @randyhoyt #orlandowordcamp
Shopping Center
Stores
Posts Pages
Sales Jobs

17. @randyhoyt #orlandowordcamp
Storing Relationships
1. Post Meta Field
2. Custom Relationship Table
3. Post Parent Field

18. @randyhoyt #orlandowordcamp
1. Post Meta Field
Talks
Speakers
Posts Pages

19. @randyhoyt #orlandowordcamp

20. @randyhoyt #orlandowordcamp
Post Meta Fields

21. @randyhoyt #orlandowordcamp
Post Meta Fields
wp_posts wp_postmeta
ID post_type post_title post_id meta_key meta_value
37 rrh_speaker Randy Hoyt 37
38 job_title
speaker Teacher
37
38 rrh_talk Custom Post Type 37 company Treehouse
Relationships
37 twitter randyhoyt

22. @randyhoyt #orlandowordcamp
Post Meta Fields
wp_posts wp_postmeta
ID post_type post_title post_id meta_key meta_value
37 rrh_speaker Randy Hoyt 37
38 job_title
speaker Teacher
37
38 rrh_talk Custom Post Type 37 company Treehouse
Relationships
37 twitter randyhoyt
38 speaker 37

23. @randyhoyt #orlandowordcamp

24. @randyhoyt #orlandowordcamp
Library: Custom Meta Boxes
http://r2h.me/wpcmb
Custom Meta Boxes allow you to build clean, understandable
interfaces for entering metadata. There’s a ton of field options:
text, textarea, checkbox, dropdown list, WYSIWYG, and more.

25. @randyhoyt #orlandowordcamp

26. @randyhoyt #orlandowordcamp

27. @randyhoyt #orlandowordcamp
$meta_boxes[] = array(
'id' => 'rrh_talk_data',
'title' => 'Talk Information',
'pages' => array('rrh_talk'),
'context' => 'normal',
'priority' => 'high',
'show_names' => true,
'fields' => array(
array(
'name' => 'Speaker',
'id' => 'speaker',
'type' => 'select',
'options' => $speakers
),
),
);

28. @randyhoyt #orlandowordcamp
$posts = query_posts( array(
'posts_per_page' => -1
'post_type' => 'rrh_speaker'
));
foreach ($posts as $post) {
$speakers[] = array(
'name' => $post->post_title,
'value' => $post->ID
);
}
wp_reset_query();

29. @randyhoyt #orlandowordcamp

30. @randyhoyt #orlandowordcamp
Template file: single-rrh_talk.php

31. Retrieve speaker ID from custom field
$speaker_id = get_post_meta($post->ID,
"speaker", true);
Retrieve speaker info from ID
$speaker = get_post($speaker_id);
Display speaker title
echo $speaker->post_title;
Retrieve link to speaker from ID
$speaker_link = get_permalink($speaker->ID);

32. @randyhoyt #orlandowordcamp
Template file: single-rrh_speaker.php

33. Retrieve talks with speaker ID in custom field
$talks = get_posts( array(
'post_type' => 'rrh_talk',
'meta_key' => 'speaker',
'meta_value' => $post->ID
));
Loop through all the talks; display talk title
foreach($talks as $talk) {
echo $talk->post_title;
}

34. @randyhoyt #orlandowordcamp

35. @randyhoyt #orlandowordcamp
2. Relationship Table
Movies
People
Posts Pages

36. @randyhoyt #orlandowordcamp
2. Relationship Table
Movies
People
Posts Pages

37. @randyhoyt #orlandowordcamp
Custom Relationship Table
wp_posts <relationship>
wp_postmeta
ID post_type post_title to_id
post_id from_id
meta_key character
meta_value
37 movie Star Wars 37
38 38
speaker Han
37 Solo
38 person Harrison Ford

38. @randyhoyt #orlandowordcamp
Plugin: Posts 2 Posts
http://r2h.me/p2p
This plugin provides functions developers can use to create
many-to-many relationships between posts of any type:
posts, pages, and custom post types.

39. @randyhoyt #orlandowordcamp

40. p2p_register_connection_type( array(
'name' => 'rrh_person_to_movie’,
'from' => 'rrh_person',
'to' => 'rrh_movie',
'fields' => array(
'role' => array(
'title' => 'Role',
'type' => 'select',
'values' => array('Director' ...)
),
'character' => array(
'title' => 'Character',
'type' => 'text'
)
),
));

41. @randyhoyt #orlandowordcamp
Custom Relationship Table
wp_posts
ID post_type post_title
37 person Harrison Ford
38 movie Star Wars
wp_p2p wp_p2pmeta
p2p_id to_id from_id type p2p_id meta_key meta_value
1 37 38 person_to_movie 1 role Lead Actor
1 character Han Solo

42. @randyhoyt #orlandowordcamp
Template file: single-rrh_movie.php

43. $connected = new WP_Query(array(
'connected_type' => 'rrh_person_to_movie',
'connected_items' => $post,
'nopaging' => true
));
if ( $connected->have_posts() ) {
...
}

44. if ( $connected->have_posts() ) {
while ( $connected->have_posts() ) :
$connected->the_post();
echo '<li><a href="';
the_permalink();
echo '">';
the_title();
echo '</a></li>';
endwhile;
}

45. @randyhoyt #orlandowordcamp
Template file: single-rrh_person.php

46. @randyhoyt #orlandowordcamp
3. Post Parent Field
Groups
Posts Pages
Meetings

47. @randyhoyt #orlandowordcamp
wp_posts
ID post_type post_title post_parent
2 page About 0
231 page Location & Venue 2
256 page Developer Hack Day 2
347 page Contact 2

48. @randyhoyt #orlandowordcamp
wp_posts
ID post_type post_title post_parent
2 page About 0
156 revision About 2
157 revision About 2
158 revision About 2

49. @randyhoyt #orlandowordcamp
wp_posts
ID post_type post_title post_parent
15 forum Book Discussions 0
78 topic Favorite Tolkien Characters? 15
123 reply Reply To: Favorite Tolkien … 78
bbPress
http://bbpress.org/

50. @randyhoyt #orlandowordcamp
Subordinate Post Type Helpers
http://wordpress.org/extend/plugins/subordinate-post-type-helpers/
This plugin provides a number of helpers functions to aid in the
creation of subordinate relationships between two post types,
one-to-many relationships in which posts of one type are children
of another.

51. @randyhoyt #orlandowordcamp
Subordinate Post Type Helpers
http://wordpress.org/extend/plugins/subordinate-post-type-helpers/
This plugin provides a number of helpers functions to aid in the
creation of subordinate relationships between two post types, one-
to-many relationships in which posts of one type are children of
another.
register_sub_post_type('meeting', $args, 'group')
;

53. Register meetings as a regular post type
register_post_type('meeting', $args)
Register meetings as a subordinate post type
register_sub_post_type('meeting', $args, 'group')

54. WordPress Codex: register_post_type()
http://codex.wordpress.org/Function_Reference/register_post_type

55. WordPress Codex: add_submenu_page()
A
http://codex.wordpress.org/Function_Reference/add_submenu_page
http://

56. add_submenu()
WordPress Codex: remove_menu_page()
A
http://codex.wordpress.org/Function_Reference/remove_menu_page
http://

57. Add_meta_boxes ()
WordPress Codex: add_meta_box()
A
http://codex.wordpress.org/Function_Reference/add_meta_box
http://

58. Add_meta_boxes ()
WordPress Codex: query_posts()
A
http://codex.wordpress.org/Function_Reference/query_posts
http://

59. Add_meta_boxes ()
WordPress Admin and Thickbox
A
<a class="thickbox" … >
http://

60. Iframe with query string parameters
Post ID parameter is left blank for adding a new meeting …

61. wp_insert_post()
Iframe with query string parameters
… but post ID parameter is set for editing an existing meeting.

62. wp_insert_post()
WordPress Codex: wp_insert_post()
http://codex.wordpress.org/Function_Reference/wp_insert_post

63. wp_insert_post()
WordPress Codex: wp_trash_post()
http://codex.wordpress.org/Function_Reference/wp_trash_post

64. JavaScript function in page
Return list of meetings to the Edit Group page

65. <script>
function list_meetings(display)
{
...
}
JavaScript function in page
</script>
Create JavaScript function on the Edit Group page

66. <script>
var display = ...
var win = window.dialogArguments →
|| opener || parent || top;
win.list_meetings(display);
</script>
Call that JavaScript function from the iframe

67. <script>
function list_meetings(display)
{
jQuery('#list_meetings).empty() →
JavaScript function .append(display);
in page
tb_remove();
}
</script>
That function inserts the list into the Edit Group page

68. JavaScript function in page

69. Register meetings as a regular post type
register_post_type('meeting', $args)
Register meetings as a subordinate post type
register_sub_post_type('meeting', $args, 'group')

70. Retrieve meetings for a group
$meetings = get_posts( array(
'post_type' => 'mythsoc_meeting',
'post_parent' => $post->ID
));
Loop through all the meetings; display meeting title
foreach($meetings as $meeting) {
echo $meeting->post_title;
}

71. @randyhoyt #orlandowordcamp
Storing Relationships
1. Post Meta Field
2. Custom Relationship Table
3. Post Parent Field

72. Relationships Between
Custom Post Types
Randy Hoyt randyhoyt.com
@randyhoyt
Presentation randyhoyt.com/wcorlando