Creating Relationships Between Content

Tujuan

1. Membuat custom post type baru: Program (contoh: Math, Biology, English)
2. Membuat relasi antara Event dan Program menggunakan ACF Relationship field
3. Setup archive dan single template untuk Programs

---

Langkah 1: Mendaftarkan Post Type "Program"

Buka wp-content/mu-plugins/university-post-types.php, tambahkan register_post_type baru di bawah event:

<?php

function university_post_types() {
  // Event post type
  register_post_type('event', array(
    'show_in_rest' => true,
    'supports' => array('title', 'editor', 'excerpt'),
    'has_archive' => true,
    'rewrite' => array('slug' => 'events'),
    'public' => true,
    'labels' => array(
      'name' => 'Events',
      'add_new_item' => 'Add New Event',
      'edit_item' => 'Edit Event',
      'all_items' => 'All Events',
      'singular_name' => 'Event'
    ),
    'menu_icon' => 'dashicons-calendar'
  ));

  // Program post type
  register_post_type('program', array(
    'show_in_rest' => true,
    'supports' => array('title', 'editor'),
    'has_archive' => true,
    'rewrite' => array('slug' => 'programs'),
    'public' => true,
    'labels' => array(
      'name' => 'Programs',
      'add_new_item' => 'Add New Program',
      'edit_item' => 'Edit Program',
      'all_items' => 'All Programs',
      'singular_name' => 'Program'
    ),
    'menu_icon' => 'dashicons-awards'
  ));
}

add_action('init', 'university_post_types');

Perbedaan Program vs Event	Penjelasan
Tidak ada 'excerpt' di supports	Program tidak perlu excerpt manual
Slug: 'programs'	URL archive: /programs
Icon: 'dashicons-awards'	Ikon piala/penghargaan

⚠️ Setelah register post type baru → buka Settings → Permalinks → Save Changes untuk rebuild permalink.

---

Langkah 2: Buat Post Contoh

Di WordPress Admin → Programs → Add New:

1. Math (+ dummy content)
2. Biology (+ dummy content)
3. English (+ dummy content)

---

Langkah 3: Template Single Program

Buat file: single-program.php di folder tema.

Copy isi dari single-event.php sebagai template awal, lalu modifikasi:

<?php get_header(); ?>

<div class="page-banner">
  <div class="page-banner__bg-image" style="background-image: url(<?php echo get_theme_file_uri('/images/ocean.jpg') ?>);">
  </div>
  <div class="page-banner__content container container--narrow">
    <h1 class="page-banner__title"><?php the_title(); ?></h1>
    <div class="page-banner__intro">
      <p><?php the_title(); ?></p>
    </div>
  </div>
</div>

<div class="container container--narrow page-section">
  <div class="metabox metabox--position-up metabox--with-home-link">
    <p>
      <a class="metabox__blog-home-link" href="<?php echo get_post_type_archive_link('program'); ?>">
        All Programs
      </a>
      <span class="metabox__main"><?php the_title(); ?></span>
    </p>
  </div>

  <div class="generic-content">
    <?php the_content(); ?>
  </div>
</div>

<?php get_footer(); ?>

---

Langkah 4: Template Archive Program

Buat file: archive-program.php di folder tema:

<?php get_header(); ?>

<div class="page-banner">
  <div class="page-banner__content container container--narrow">
    <h1 class="page-banner__title">All Programs</h1>
    <div class="page-banner__intro">
      <p>There is something for everyone. Have a look around.</p>
    </div>
  </div>
</div>

<div class="container container--narrow page-section">
  <ul class="link-list min-list">
    <?php
      while (have_posts()) {
        the_post(); ?>
        <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
      <?php } ?>
  </ul>

  <?php echo paginate_links(); ?>
</div>

<?php get_footer(); ?>

---

Langkah 5: Urutkan Programs Alfabetis (pre_get_posts)

Di functions.php, tambahkan kondisi baru di dalam fungsi university_adjust_queries:

function university_adjust_queries($query) {
  if (!is_admin() AND is_post_type_archive('program') AND $query->is_main_query()) {
    $query->set('orderby', 'title');
    $query->set('order', 'ASC');
    $query->set('posts_per_page', -1);
  }

  if (!is_admin() AND is_post_type_archive('event') AND $query->is_main_query()) {
    $today = date('Ymd');
    $query->set('meta_key', 'event_date');
    $query->set('orderby', 'meta_value_num');
    $query->set('order', 'ASC');
    $query->set('meta_query', array(
      array(
        'key' => 'event_date',
        'compare' => '>=',
        'value' => $today,
        'type' => 'numeric'
      )
    ));
  }
}

add_action('pre_get_posts', 'university_adjust_queries');

Parameter	Nilai	Penjelasan
orderby	'title'	Urutkan berdasarkan judul (abjad)
order	'ASC'	A → Z
posts_per_page	-1	Tampilkan semua program di satu halaman

---

Langkah 6: Membuat Relationship Field (ACF)

Buat Field Group Baru

1. WordPress Admin → Custom Fields → Add New
2. Nama: Related Program(s)
3. Klik Add Field:

Setting	Nilai
Field Label	Related Program(s)
Field Name	related_programs
Field Type	Relationship (di bawah kategori "Relational")
Filter by Post Type	Program
Filters	Hanya Search (hapus Post Type & Taxonomy)
Return Format	Post Object (default)

4. Location: Show this field group if Post Type = Event
5. Klik Publish

Menggunakan Relationship Field

Edit event post (contoh: Science of Cats):

• Scroll ke bawah → field Related Programs
• Kolom kiri: daftar semua program
• Klik program → pindah ke kolom kanan (terpilih)
• Contoh: pilih Biology

💡 Relationship field mengembalikan array of post objects — bisa berisi satu atau banyak relasi.