CREATE TABLE `messages_new` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `concrete_message_type` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
  `concrete_message_id` int(11) DEFAULT NULL,
  `sent_at` int(11) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_messages_on_concrete_message_id` (`concrete_message_id`),
  KEY `sent_at_index` (`sent_at`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci