Programmatically translate a string in hook_update_N()

Question

Is there a function I can use to perform a string translation in hook_update_N()?

Answer 1

Yes, you can check in the locale module how it's done and replicate to use the same queries like this :

/**
 * Translating some pagination strings.
 */
function hook_update_XXXX() {
  $translations = array(
   'last' => array(
     'fr' => 'dernière page',
     'en-en' => 'last',
   ),
   'first' => array(
     'fr' => 'première page',
     'en-en' => 'first',
   ),
 );

 foreach ($translations as $string => $values) {
   $source = db_query('SELECT lid, source, context, textgroup, location FROM {locales_source} WHERE source = :string', array(':string' => $string))->fetchObject();
  if (!$source) {
    watchdog('update_hook', 'Translation of string "%string" failed.', array('%string%' => $string));
    continue;
  }

  foreach ($values as $langcode => $translated) {
    $translation = db_query('SELECT translation FROM {locales_target} WHERE lid = :lid AND language = :language', array(':lid' => $source->lid, ':language' => $langcode))->fetchField();
    if (is_string($translation)) {
      db_update('locales_target')
      ->fields(array('translation' => $translated))
      ->condition('lid', $source->lid)
      ->condition('language', $langcode)
      ->execute();
    }
    else {
      db_insert('locales_target')
      ->fields(array(
        'lid' => $source->lid,
        'translation' => $translated,
        'language' => $langcode,
      ))
      ->execute();
      }
    }
  }
}

I'm using such code to update strings in code instead of having to this manually when deploying code. So a simple "drush updb" can do the job for me.

OR as I've found out recently, a faster version exists like this :

/**
 * Translating some strings.
 */
function hook_update_X() {
  $report = array(
    'skips'=> 0,
    'updates'=> 0,
    'deletes'=> 0,
    'additions'=> 0
  );

  // Translate strings.
  _locale_import_one_string_db($report, 'fr', '', 'Your shipping address book is currently empty.', 'Votre carnet d\'adresses de livraison est actuellement vide.', 'default', '', LOCALE_IMPORT_OVERWRITE);
  _locale_import_one_string_db($report, 'fr', '', 'Your billing address book is currently empty.', 'Votre carnet d\'adresses de facturation est actuellement vide.', 'default', '', LOCALE_IMPORT_OVERWRITE);

  // Clear locale cache.
  cache_clear_all('locale:', 'cache', TRUE);
}

For Drupal 8, please see this answer : https://drupal.stackexchange.com/a/220608/61138