创建表时直接设置:

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
? `stu_id` int(11) NOT NULL AUTO_INCREMENT,
? `name` varchar(255) DEFAULT NULL,
? PRIMARY KEY (`stu_id`),
? UNIQUE KEY `UK_student_name` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=12 DEFAULT CHARSET=utf8;

?

?

创建唯一索引:

create unique index UK_student_name on student (name);

?

建表后添加约束:

alter table student add constraint uk_student_name unique (name);