ALTER TABLE `vn`.`workerLog` 
    ADD COLUMN `changedModel` VARCHAR(45) NULL DEFAULT NULL AFTER `description`,
    ADD COLUMN `oldInstance` text CHARACTER SET utf8 COLLATE utf8_unicode_ci,
    ADD COLUMN  `newInstance` text CHARACTER SET utf8 COLLATE utf8_unicode_ci,
    ADD COLUMN `changedModelId` int(11) DEFAULT NULL,
    ADD COLUMN `changedModelValue` varchar(45) CHARACTER SET utf8 COLLATE utf8_unicode_ci DEFAULT NULL;