MySQL modifies the table structure and its functions of adding, deleting and modifying fields

MySQL modify table structure add delete modify fields

Create database

CREATE DATABASE database_name

Create table

CREATE TABLE `user` ( `id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT 'ID', PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8;

Delete table

DROP TABLE IF EXISTS `user`;

Add field:

"ALTER TABLE `user` ADD `id` int(11) NOT NULL DEFAULT '0' COMMENT 'ID'" ALTER TABLE `user` ADD `name` VARCHAR( 20 ) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '姓名'

Delete field

ALTER TABLE `user` DROP column name

Rename

ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;

Modify type

alter table t1 change b b bigint not null; alter table infos change list list tinyint not null default '0';

Add index

alter table t1 rename t2; 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;修改表：

Add fields in Thinkphp3.2, such as:

M('admin')->execute("ALTER TABLE `admin` ADD `id` int(11) NOT NULL DEFAULT '0' COMMENT 'ID'"); M('admin')->execute("ALTER TABLE `admin` ADD `name` varchar(20) DEFAULT NULL COMMENT '姓名'");

Recommended tutorial: "Mysql"

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