错误码: 1068
Multiple primary key defined
Execution Time : 00:00:00:000
Transfer Time : 00:00:00:000
Total Time : 00:00:00:000
解决办法：
DROP TABLE IF EXISTS pre_common_syscache;
CREATE TABLE pre_common_syscache (
cname varchar(32) NOT NULL,
ctype tinyint(3) unsigned NOT NULL,
dateline int(10) unsigned NOT NULL,
`data` mediumblob NOT NULL,
PRIMARY KEY (cname)
) TYPE=MyISAM;
重新运行升级程序即可。
Discuz升级 Database Error : pre_common_syscache ADD PRIMARY KEY (cname)【解决办法】
原文：http://www.cnblogs.com/jyb2014/p/4095002.html