blog » MySQL » mysql表结构修改

mysql表结构修改

增加字段:

ALTER TABLE table_name ADD field_name field_type;

//增加一个新列

alter table t2 add d timestamp;
alter table infos add ex tinyint not null default ‘0’;

如果需要指定新增字段的位置,使用如下语法:

alter table `user_movement_log` Add column GatewayId int not null default 0 AFTER `Regionid`;

修改原字段名称及类型:

ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;

//重命名列
alter table t1 change a b integer;

//改变列的类型
alter table t1 change b b bigint not null;
alter table infos change list list tinyint not null default ‘0’;

调整字段顺序:
ALTER TABLE `user_movement_log` CHANGE `GatewayId` `GatewayId` int not null default 0 AFTER RegionID

删除字段:

alter table `user_movement_log` drop column Gatewayid

删除字段:

mysql> ALTER TABLE table_name DROP field_name;

//主键

alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);

加索引

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

mysql> alter table tablename add primary key(id);

加唯一限制条件的索引

mysql> alter table tablename add unique emp_name2(cardnumber);

删除某个索引

mysql>alter table tablename drop index emp_name;

//重命名表
alter table t1 rename t2;

This post has already been read 19 times!

Related posts

RSS 2.0 | leave a response | trackback

发表评论