mysql通过修改表添加唯一键案例,将name设为唯一键代码如下:
- mysql> alter table stu28 add unique(name);
复制代码 -- 将name,addr设为唯一键
- mysql> alter table stu28 add unique(name),add unique(addr);
- Query OK, 0 rows affected (0.00 sec)
- Records: 0 Duplicates: 0 Warnings: 0
复制代码 运行显示结果如下:
- mysql> desc stu28;
- +-------+-------------+------+-----+---------+-------+
- | Field | Type | Null | Key | Default | Extra |
- +-------+-------------+------+-----+---------+-------+
- | id | int(11) | NO | PRI | NULL | |
- | name | varchar(20) | YES | UNI | NULL | |
- | addr | varchar(20) | YES | UNI | NULL | |
- +-------+-------------+------+-----+---------+-------+
- 3 rows in set (0.02 sec)
复制代码
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