drupal/core/modules/forum/forum.install

<?php

/**
 * @file
 * Install, update, and uninstall functions for the Forum module.
 */

use Drupal\field\Entity\FieldStorageConfig;
use Drupal\taxonomy\Entity\Term;

/**
 * Implements hook_install().
 */
function forum_install($is_syncing) {
  // Set the weight of the forum.module to 1 so it is loaded after the taxonomy.module.
  module_set_weight('forum', 1);
  // Do not allow to delete the forum's node type machine name.
  $locked = \Drupal::state()->get('node.type.locked');
  $locked['forum'] = 'forum';
  \Drupal::state()->set('node.type.locked', $locked);

  if (!$is_syncing) {
    // Create a default forum so forum posts can be created.
    $term = Term::create([
      'name' => t('General discussion'),
      'description' => '',
      'parent' => [0],
      'vid' => 'forums',
      'forum_container' => 0,
    ]);
    $term->save();
  }
}

/**
 * Implements hook_uninstall().
 */
function forum_uninstall() {
  if ($field_storage = FieldStorageConfig::loadByName('node', 'taxonomy_forums')) {
    $field_storage->delete();
  }

  if ($field_storage = FieldStorageConfig::loadByName('node', 'comment_forum')) {
    $field_storage->delete();
  }

  if ($field_storage = FieldStorageConfig::loadByName('taxonomy_term', 'forum_container')) {
    $field_storage->delete();
  }

  // Purge field data now to allow taxonomy and options module to be uninstalled
  // if this is the only field remaining.
  field_purge_batch(10);
  // Allow to delete a forum's node type.
  $locked = \Drupal::state()->get('node.type.locked');
  unset($locked['forum']);
  \Drupal::state()->set('node.type.locked', $locked);
}

/**
 * Implements hook_schema().
 */
function forum_schema() {
  $schema['forum'] = [
    'description' => 'Stores the relationship of nodes to forum terms.',
    'fields' => [
      'nid' => [
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The {node}.nid of the node.',
      ],
      'vid' => [
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'Primary Key: The {node}.vid of the node.',
      ],
      'tid' => [
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The {taxonomy_term_data}.tid of the forum term assigned to the node.',
      ],
    ],
    'indexes' => [
      'forum_topic' => ['nid', 'tid'],
      'tid' => ['tid'],
    ],
    'primary key' => ['vid'],
    'foreign keys' => [
      'forum_node' => [
        'table' => 'node',
        'columns' => [
          'nid' => 'nid',
          'vid' => 'vid',
        ],
      ],
    ],
  ];

  $schema['forum_index'] = [
    'description' => 'Maintains denormalized information about node/term relationships.',
    'fields' => [
      'nid' => [
        'description' => 'The {node}.nid this record tracks.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ],
      'title' => [
        'description' => 'The node title.',
        'type' => 'varchar',
        'length' => 255,
        'not null' => TRUE,
        'default' => '',
      ],
      'tid' => [
         'description' => 'The term ID.',
         'type' => 'int',
         'unsigned' => TRUE,
         'not null' => TRUE,
         'default' => 0,
      ],
      'sticky' => [
        'description' => 'Boolean indicating whether the node is sticky.',
        'type' => 'int',
        'not null' => FALSE,
        'default' => 0,
        'size' => 'tiny',
      ],
      'created' => [
        'description' => 'The Unix timestamp when the node was created.',
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
      ],
      'last_comment_timestamp' => [
        'type' => 'int',
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The Unix timestamp of the last comment that was posted within this node, from {comment}.timestamp.',
      ],
      'comment_count' => [
        'type' => 'int',
        'unsigned' => TRUE,
        'not null' => TRUE,
        'default' => 0,
        'description' => 'The total number of comments on this node.',
      ],
    ],
    'indexes' => [
      'forum_topics' => ['nid', 'tid', 'sticky', 'last_comment_timestamp'],
      'created' => ['created'],
      'last_comment_timestamp' => ['last_comment_timestamp'],
    ],
    'foreign keys' => [
      'tracked_node' => [
        'table' => 'node',
        'columns' => ['nid' => 'nid'],
      ],
      'term' => [
        'table' => 'taxonomy_term_data',
        'columns' => [
          'tid' => 'tid',
        ],
      ],
    ],
  ];

  return $schema;
}