ALTER TABLE `zt_file` CHANGE `pathname` `pathname` char(100) NOT NULL; TRUNCATE `zt_im_usermessage`; ALTER TABLE `zt_im_usermessage` DROP `module`; ALTER TABLE `zt_im_usermessage` DROP `method`; ALTER TABLE `zt_im_usermessage` CHANGE `data` `message` text not null; DROP TABLE IF EXISTS `zt_im_chatfile`;