mysql 怎么删除唯一约束? 表名 nnn 列名 myname(可以为空) 想删除唯一约束 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 Google找了半天,很无力~~,只找到创建,没找到删除真是只管结婚不管生孩子~~~~ show create table nnn;贴一下内容。 mysql> show create table nnn;+-------+----------------------------------------------------------------------------------------------------------------------------------------+| Table | Create Table |+-------+----------------------------------------------------------------------------------------------------------------------------------------+| nnn | CREATE TABLE `nnn` ( `id` int(11) NOT NULL auto_increment, `myname` varchar(20) default NULL, PRIMARY KEY (`id`), UNIQUE KEY `myname` (`myname`)) ENGINE=InnoDB DEFAULT CHARSET=gb2312 |+-------+----------------------------------------------------------------------------------------------------------------------------------------+1 row in set (0.00 sec)大哥,我找你好久了 mysql> show create table `nnn`;+-------+------------------------------------| Table | Create Table+-------+------------------------------------| nnn | CREATE TABLE `nnn` ( `id` int(11) NOT NULL AUTO_INCREMENT, `myname` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `myname` (`myname`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+-------+------------------------------------1 row in set (0.00 sec)mysql> DROP INDEX `myname` ON `nnn`;Query OK, 0 rows affected (0.13 sec)Records: 0 Duplicates: 0 Warnings: 0mysql> show create table `nnn`;+-------+-------------------------------| Table | Create Table+-------+-------------------------------| nnn | CREATE TABLE `nnn` ( `id` int(11) NOT NULL AUTO_INCREMENT, `myname` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+-------+-------------------------------1 row in set (0.00 sec)mysql> 小菜不理解为什么删除INDEX,不是创建唯一约束了吗。。 或者 alter table `nnn` drop `myname`;mysql> show create table `nnn`;+-------+------------------------------------| Table | Create Table+-------+------------------------------------| nnn | CREATE TABLE `nnn` ( `id` int(11) NOT NULL AUTO_INCREMENT, `myname` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`), UNIQUE KEY `myname` (`myname`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+-------+------------------------------------1 row in set (0.00 sec)mysql> alter table `nnn` drop `myname`;Query OK, 0 rows affected (0.14 sec)Records: 0 Duplicates: 0 Warnings: 0mysql> show create table `nnn`;+-------+-------------------------------| Table | Create Table+-------+-------------------------------| nnn | CREATE TABLE `nnn` ( `id` int(11) NOT NULL AUTO_INCREMENT, `myname` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=latin1 |+-------+-------------------------------1 row in set (0.00 sec)mysql> ora-00907 缺失右括号????? 100110011100011100111统计1的个数,小弟先谢了哈! 建立外键关联出现错误 数据库安装目录下的ErrorLog日志文件可不可以删除 在JSP页面自动生成带有日期和数字的序列号 请教SQL语句! 关于SQL2005的Update 多层外连接时,报错DB-Library Process Dead 如何在ORACLE中存入图片? 为什么显示条数和数据条数不同? 向表中插入日期,怎么出错了啊? 求VB+SQL分行书写格式!!!
+-------+------------------------------------------
---------------------------------------------------
-------------------------------------------+
| Table | Create Table |
+-------+------------------------------------------
---------------------------------------------------
-------------------------------------------+
| nnn | CREATE TABLE `nnn` (
`id` int(11) NOT NULL auto_increment,
`myname` varchar(20) default NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `myname` (`myname`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312 |
+-------+------------------------------------------
---------------------------------------------------
-------------------------------------------+
1 row in set (0.00 sec)大哥,我找你好久了
+-------+------------------------------------
| Table | Create Table
+-------+------------------------------------
| nnn | CREATE TABLE `nnn` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`myname` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `myname` (`myname`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+------------------------------------
1 row in set (0.00 sec)mysql> DROP INDEX `myname` ON `nnn`;
Query OK, 0 rows affected (0.13 sec)
Records: 0 Duplicates: 0 Warnings: 0mysql> show create table `nnn`;
+-------+-------------------------------
| Table | Create Table
+-------+-------------------------------
| nnn | CREATE TABLE `nnn` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`myname` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-------------------------------
1 row in set (0.00 sec)mysql>
小菜不理解为什么删除INDEX,不是创建唯一约束了吗。。
+-------+------------------------------------
| Table | Create Table
+-------+------------------------------------
| nnn | CREATE TABLE `nnn` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`myname` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `myname` (`myname`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+------------------------------------
1 row in set (0.00 sec)mysql> alter table `nnn` drop `myname`;
Query OK, 0 rows affected (0.14 sec)
Records: 0 Duplicates: 0 Warnings: 0mysql> show create table `nnn`;
+-------+-------------------------------
| Table | Create Table
+-------+-------------------------------
| nnn | CREATE TABLE `nnn` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`myname` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-------------------------------
1 row in set (0.00 sec)mysql>