materio-base-d7/sites/all/modules/contrib/fields/cer/cer.install

<?php

/**
 * @file
 * Install file providing corresponding entity reference schema.
 */

/**
 * Implements hook_schema().
 */
function cer_schema() {
  $schema['cer'] = array(
    'description' => t('Saves the content types and entity reference fields for which the corresponding entity reference is enabled'),
    'fields' => array(
      'entity_types_content_fields' => array('type' => 'varchar', 'length' => 200, 'not null' => TRUE, 'default' => ''),
      'enabled' => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
    ),
    'primary key' => array('entity_types_content_fields'),
    'export' => array(
      'key' => 'entity_types_content_fields',
      'status' => 'enabled',
      'primary key' => 'entity_types_content_fields',
      'key name' => 'Corresponding entity reference',
      'identifier' => 'cnr_obj',
      'api' => array(
        'api' => 'default_cer_presets',
        'owner' => 'cer',
        'minimum_version' => 1,
        'current_version' => 1,
      ),
    ),
  );
  return $schema;
}

/**
 * Rename table to shorten module name.
 */
function cer_update_7001() {
  db_rename_table('corresponding_entity_references', 'cer');
}

/**
 * Disable presets which refer to fields that don't exist. (Issue #2122531)
 */
function cer_update_7002() {
  $presets = db_query('SELECT entity_types_content_fields FROM {cer} WHERE 1')->fetchCol();

  foreach ($presets as $preset) {
    $keys = explode('*', $preset);
    
    $left = field_info_instance($keys[0], $keys[2], $keys[1]);
    $right = field_info_instance($keys[3], $keys[5], $keys[4]);

    if (empty($left) || empty($right)) {
      db_query('UPDATE {cer} SET enabled = 0 WHERE entity_types_content_fields = :preset', array(':preset' => $preset));
      drupal_set_message(t('CER preset %preset was disabled because it uses non-existent fields.', array('%preset' => $preset)), 'warning');
    }
  }
}