PRIMARY KEY (`ct_id`),
  UNIQUE KEY `change_tag_rc_tag_id` (`ct_rc_id`,`ct_tag_id`),
  UNIQUE KEY `change_tag_log_tag_id` (`ct_log_id`,`ct_tag_id`),
  UNIQUE KEY `change_tag_rev_tag_id` (`ct_rev_id`,`ct_tag_id`),
  KEY `change_tag_tag_id` (`ct_tag`,`ct_rc_id`,`ct_rev_id`,`ct_log_id`),
  KEY `change_tag_tag_id_id` (`ct_tag_id`,`ct_rc_id`,`ct_rev_id`,`ct_log_id`),
  KEY `change_tag_rc_tag_nonuniq` (`ct_rc_id`,`ct_tag`),
  KEY `change_tag_log_tag_nonuniq` (`ct_log_id`,`ct_tag`),
  KEY `change_tag_rev_tag_nonuniq` (`ct_rev_id`,`ct_tag`)