mysql alter 语句用法,添加、修改、删除字段等
http://www.blogjava.net/Alpha/archive/2007/07/23/131912.html
//主键549830479
alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);
//增加一个新列549830479
alter table t2 add d timestamp;
alter table infos add ex tinyint not null default '0';
例2:alter table msglogabstract add subcaption int(255) default 0;
//删除列549830479
alter table t2 drop column c;
//重命名列549830479
alter table t1 change a b integer;
//改变列的类型549830479
alter table t1 change b b bigint not null;
alter table infos change list list tinyint not null default '0';
//重命名表549830479
alter table t1 rename t2;
加索引549830479
mysql> alter table tablename change depno depno int(5) not null;
mysql> alter table tablename add index 索引名 (字段名1[,字段名2 …]);
mysql> alter table tablename add index emp_name (name);
加主关键字的索引549830479
mysql> alter table tablename add primary key(id);
加唯一限制条件的索引549830479
mysql> alter table tablename add unique emp_name2(cardnumber);
删除某个索引549830479
mysql>alter table tablename drop index emp_name;
修改表:549830479
增加字段:549830479
mysql> ALTER TABLE table_name ADD field_name field_type;
修改原字段名称及类型:549830479
mysql> ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;
删除字段:549830479
mysql> ALTER TABLE table_name DROP field_name;
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打开命令行窗口,停止mysql服务(或者在任务管理器里结束掉mysqld-nt.exe进程): Net stop mysql
启动mysql,一般到mysql的安装路径,找到 mysqld-nt.exe
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另外打开一个命令行窗口,执行mysql
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Query OK, 1 row affected (0.00 sec)
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+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql & ......
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解决办法:url=url=+"?useUnicode=true& ......
mysql
> SHOW VARIABLES LIKE
'character_set_%';
+--------------------------+----------------------------+
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latin1 |
| character_set ......
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MySQL服务器的默认编码是Latin1,不支持中文,那么如何修改MySQL的默认编码呢,下面以UTF-8为例来说明。
1、中止MySQL服务(bin/mysqladmin -u root shutdown)
2、在/etc/下找到my.cnf,如果没有就把MySQL的安装目录下的support-files目录下的my-medium.cnf复制到/etc/下并改名为my.cnf即可
......