怎么删除唯一约束?菜鸟求救!! 表名 nnn 列名 myname(可以为空) 想删除唯一约束 ALTER TABLE nnn drop UNIQUE (myname);删不掉 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 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)大哥让你久等了!!! 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> 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> 我是个新手想多学习PHP谁能给我一本这方面入门级别的书啊。。。 PHP实现页面间数据传递的问题,请帮助. 怎么提取一个字符串中,字符类型的个数 检索分页疑难问题,求助高手~ 怎么样以Apache 模块安装PHP?? 请教一个简单的速度问题?? 关于特殊字符的过滤...我这有80分。。 求一段程序. 急!急!急!eregi怎么用呢? 每个分页都有自己的php分页下标,但是无论点击哪个分页的下标如“下一页”都不能直接显示出来而显示的是所有分页所在的页面,如何一步到为呢? MYSQL与Smarty的应用 求教PHP算法问题
+-------+------------------------------------------
---------------------------------------------------
-------------------------------------------+
| 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)大哥让你久等了!!!
+-------+------------------------------------
| 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>
+-------+------------------------------------
| 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>