Quickly modify the table structure of a MySQL table

quickly modify the table structure of a MySQL table-- excerpt from "MySQL Management"

ALTER table name MODIFY column name data type; This command can modify the table structure

In addition, you can modify the table structure as follows:

First create a table, as follows:

> CREATE table t1 (id int, name varchar (5), RMB decimal (9,1));

If you want to modify the Name column varchar (10), you can do this: ALTER TABLE T1 modify name varchar (7);

You can also do the following:

1. View the table structure as follows:

> use test;> desc t1;+-------+--------------+------+-----+---------+-------+|  field | type         | null | key |  default | extra |+-------+--------------+------+-----+---------+-------+| id     | int (one)       | YES  |      | null    |       | |  name  | varchar (5)    | YES  |      | null    |       | |  rmb   | decimal (9,1)  | yes  |     |  null    |       |+-------+--------------+------+- ----+---------+-------+3 rows in set  (0.00&nbsP;SEC) 

2. Create a temporary table and set the varchar to 10:

> CREATE table t1_tmp (ID int, name varchar (), RMB decimal (9,1));

3, replace the. FRM table structure file

> Flush tables with read lock; Lock the table first and put the table open to avoid data loss. > System cp/usr/local/mariadb/var/test/t1_tmp.frm/usr/local/mariadb/var/test/t1.frm

4. Unlock the Lock

> Unlock tables;

5. View table structure

> Show CREATE TABLE t1\g*************************** 1. Row *************************** table:t1create table:create Table ' t1 ' (' id ' int (one) DEFAULT NULL, ' name ' Varch AR (TEN) default NULL, ' $ ' decimal (9,1) default null) Engine=innodb default charset=utf81 row in Set (0.00 sec)

You can see the varchar (10) of the Name column.

6. Insert Bar Data test

> INSERT into T1 values (2, ' Hechuangyang ', 3.8); If you don't make an error, the change is successful.

Quickly modify the table structure of a MySQL table