MySQL/MariaDBSQL修改表字段类型、备份数据库

1、修改表字段类型

alter table nodes modify column info varchar(200)

示例操作入下：

MariaDB [dbmanager]> alter table nodes modify column info varchar(200);
Query OK, 0 rows affected (0.02 sec)               
Records: 0  Duplicates: 0  Warnings: 0

MariaDB [dbmanager]> desc nodes;
+-----------+--------------+------+-----+---------------------+-------------------------------+
| Field     | Type         | Null | Key | Default             | Extra                         |
+-----------+--------------+------+-----+---------------------+-------------------------------+
| id        | varchar(36)  | NO   | PRI | NULL                |                               |
| nodename  | varchar(20)  | YES  |     | NULL                |                               |
| ip        | varchar(20)  | YES  |     | NULL                |                               |
| username  | varchar(20)  | YES  |     | NULL                |                               |
| password  | varchar(20)  | YES  |     | NULL                |                               |
| os        | varchar(20)  | YES  |     | NULL                |                               |
| pubkey    | varchar(400) | YES  |     | NULL                |                               |
| role      | varchar(100) | YES  |     | NULL                |                               |                              |
| sn        | int(10)      | YES  |     | NULL                |                               |
| info      | varchar(200) | YES  |     | NULL                |                               |
| status    | int(10)      | YES  |     | NULL                |                               |                           |
+-----------+--------------+------+-----+---------------------+-------------------------------+
14 rows in set (0.01 sec)

MariaDB [dbmanager]> 

2、备份数据库

mysqldump -h hostname -uroot -p dbname > /root/sql/bak.sql

示例操作

[root@hadron ~]# mysqldump -h master -uroot -p123456 dbmanager > /root/sql/bak.sql
[root@hadron ~]# ll sql|grep bak.sql
-rw-r--r-- 1 root root 25908 11月 28 09:34 bak.sql
[root@hadron ~]#