performance-art.fr/sites/all/modules/contrib/search/search_api_db/search_api_db.module

<?php

/**
 * Implements hook_search_api_service_info().
 */
function search_api_db_search_api_service_info() {
  $services['search_api_db_service'] = array(
    'name' => t('Database service'),
    'description' => t('<p>Index items using multiple database tables, for simple searches.</p>' .
        '<ul>' . '<li>All field types are supported and indexed in a special way, with URI/String and Integer/Duration being equivalent.</li>' .
        '<li>The "direct" parse mode results in the keys being normally split around white-space, only preprocessing might differ.</li>' .
        '<li>Currently, phrase queries are not supported. Additionally, due to MySQL limitations, all searches will be case-insensitive.</li>' . '</ul>'),
    'class' => 'SearchApiDbService',
  );
  return $services;
}