如何在mysql中对json类型列建立唯一索引？例如，我有一个带有slug属性的translations列。我需要一个独特的slug之间的语言翻译栏图像 CREATE TABLEposts(idint(10) unsigned NOT NULL AUTO_INCREMENT,user_idint(10) unsigned NOT NULL,root_idint(10) unsigned NOT NULL,translationslongtext COLLATE utf8mb4_unicode_ci NOT NULL,published_fromtimestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,published_tilltimestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,display_datetimestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,imageslongtext COLLATE utf8mb4_unicode_ci,deleted_attimestamp NULL DEFAULT NULL,created_attimestamp NULL DEFAULT NULL,updated_attimestamp NULL DEFAULT NULL, PRIMARY KEY (id), KEYposts_user_id_foreign(user_id), KEYposts_root_id_foreign(root_id), CONSTRAINTposts_root_id_foreignFOREIGN KEY (root_id) REFERENCESroots(id) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINTposts_user_id_foreignFOREIGN KEY (user_id) REFERENCESadmins(id) ON UPDATE CASCADE ) ENGINE=InnoDB AUTO_INCREMENT=13 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;