CentOS6.5下简单的MySQL数据库操作
1.登录成功之后退出的话,直接输入quit或者exit即可。
2.使用.tar.gz的包安装MySQL时,进入MySQL需要使用绝对路径
[root@winner ~]# /usr/local/mysql/bin/mysql -uroot
单独只是输入一个"mysql" 命令是不行的,因为"/usr/local/mysql/bin" 没有在 PATH 这个环境变量里(使用yum安装不需要)。如何把它加入环境变量PATH中?
[root@winner ~]# PATH=$PATH:/usr/local/mysql/bin
这样就可以了,但重启Linux后还会失效,所以需要让它开机加载:
[root@winner ~]# echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile [root@winner ~]# source /etc/profile [root@localhost ~]# mysql -uroot
-u 用来指定要登录的用户,后边可以有空格,也可以无空格。-p 后面可以直接跟密码,后面不可以有空格,不过密码最好用单引号括起来,不括也可以,但是密码中如果有特殊字符就会有问题了,所以最好是括起来。
连接数据库
通过使用 mysql -u root -p
可以连接数据库,但这只是连接的本地的数据库"localhost", 可是有很多时候都是去连接网络中的某一个主机上的mysql。
[root@winner ~]# mysql -uroot -p -h192.168.137.10 -P3306 Enter password:
其中后边的 -P(大写) 用来指定远程主机MySQL的绑定端口,默认都是3306, -h 用来指定远程主机的IP.
一些基本的MySQL操作命令
1. 查询当前的库
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | test | | winner | +--------------------+ rows in set (0.07 sec)
2. 查询某个库的表
首先需要切换到某个库中 mysql> use mysql Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed 显示该数据库中的表 mysql> show tables; +---------------------------+ | Tables_in_mysql | +---------------------------+ | columns_priv | | db | | event | | func | | general_log | | help_category | | help_keyword | | help_relation | | help_topic | | host | | ndb_binlog_index | | plugin | | proc | | procs_priv | | servers | | slow_log | | tables_priv | | time_zone | | time_zone_leap_second | | time_zone_name | | time_zone_transition | | time_zone_transition_type | | user | +---------------------------+ rows in set (0.00 sec)
3. 查看某个表的全部字段
mysql> desc host; +-----------------------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------------------+---------------+------+-----+---------+-------+ | Host | char(60) | NO | PRI | | | | Db | char(64) | NO | PRI | | | | Select_priv | enum('N','Y') | NO | | N | | | Insert_priv | enum('N','Y') | NO | | N | | | Update_priv | enum('N','Y') | NO | | N | | | Delete_priv | enum('N','Y') | NO | | N | | | Create_priv | enum('N','Y') | NO | | N | | | Drop_priv | enum('N','Y') | NO | | N | | | Grant_priv | enum('N','Y') | NO | | N | | | References_priv | enum('N','Y') | NO | | N | | | Index_priv | enum('N','Y') | NO | | N | | | Alter_priv | enum('N','Y') | NO | | N | | | Create_tmp_table_priv | enum('N','Y') | NO | | N | | | Lock_tables_priv | enum('N','Y') | NO | | N | | | Create_view_priv | enum('N','Y') | NO | | N | | | Show_view_priv | enum('N','Y') | NO | | N | | | Create_routine_priv | enum('N','Y') | NO | | N | | | Alter_routine_priv | enum('N','Y') | NO | | N | | | Execute_priv | enum('N','Y') | NO | | N | | | Trigger_priv | enum('N','Y') | NO | | N | | +-----------------------+---------------+------+-----+---------+-------+ rows in set (0.00 sec)
也可以使用另一条命令,显示比这个更详细,而且可以把建表语句全部列出来:
mysql> show create table host\G; *************************** 1. row *************************** Table: host Create Table: CREATE TABLE `host` ( `Host` char(60) COLLATE utf8_bin NOT NULL DEFAULT '', `Db` char(64) COLLATE utf8_bin NOT NULL DEFAULT '', `Select_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Insert_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Update_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Delete_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Create_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Drop_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Grant_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `References_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Index_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Alter_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Create_tmp_table_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Lock_tables_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Create_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Show_view_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Create_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Alter_routine_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Execute_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', `Trigger_priv` enum('N','Y') CHARACTER SET utf8 NOT NULL DEFAULT 'N', PRIMARY KEY (`Host`,`Db`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='Host privileges; Merged with database privileges' row in set (0.00 sec)
4. 查看当前是哪个用户
mysql> select user(); +----------------+ | user() | +----------------+ | root@localhost | +----------------+ row in set (0.00 sec)
5. 查看当前所使用数据库
mysql> select database(); +------------+ | database() | +------------+ | mysql | +------------+ row in set (0.00 sec)
6. 创建一个新库
mysql> create database db1; Query OK, 1 row affected (0.02 sec)
7. 创建一个新表
mysql> create table t1 (`id` int(4), `name` char(40)); Query OK, 0 rows affected (0.02 sec)
8. 查看当前数据库版本
mysql> select version(); +-----------+ | version() | +-----------+ | 5.1.73 | +-----------+ row in set (0.00 sec)
9. 查看当前MySQL状态
mysql> show status; +-----------------------------------+----------+ | Variable_name | Value | +-----------------------------------+----------+ | Aborted_clients | 1 | | Aborted_connects | 2 | | Binlog_cache_disk_use | 0 | | Binlog_cache_use | 0 | | Bytes_received | 1194 | | Bytes_sent | 21732 | | Com_admin_commands | 0 | | Com_assign_to_keycache | 0 | | Com_alter_db | 0 | | Com_alter_db_upgrade | 0 | | Com_alter_event | 0 |
10. 查看MySQL的参数
mysql> show variables; +-----------------------------------------+---------------------+ | Variable_name | Value | +-----------------------------------------+---------------------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | | autocommit | ON | | automatic_sp_privileges | ON | | back_log | 50 | | basedir | /usr/local/mysql/ |
11. 修改MySQL的参数
mysql> show variables like 'max_connect%'; +--------------------+-------+ | Variable_name | Value | +--------------------+-------+ | max_connect_errors | 10 | | max_connections | 151 | +--------------------+-------+ rows in set (0.00 sec) mysql> set global max_connect_errors = 1000; Query OK, 0 rows affected (0.00 sec) mysql> show variables like 'max_connect_errors'; +--------------------+-------+ | Variable_name | Value | +--------------------+-------+ | max_connect_errors | 1000 | +--------------------+-------+ row in set (0.00 sec)
在MySQL命令行, "%"类似于shell下的 *
, 表示万能匹配。使用 "set global" 可以临时修改某些参数,但是重启mysqld服务后还会变为原来的,所以要想恒久生效,需要在配置文件 my.cnf 中定义。
12. 查看当前MySQL服务器的队列
这个在日常的管理工作中使用最为频繁,因为使用它可以查看当前mysql在干什么,可以发现是否有锁表:
mysql> show processlist; +----+------+-----------+------+---------+------+-------+------------------+ | Id | User | Host | db | Command | Time | State | Info | +----+------+-----------+------+---------+------+-------+------------------+ | 9 | root | localhost | db1 | Query | 0 | NULL | show processlist | +----+------+-----------+------+---------+------+-------+------------------+ row in set (0.00 sec)
13. 创建一个普通用户并授权
mysql> grant all on *.* to user1 identified by '123456'; Query OK, 0 rows affected (0.01 sec)
all 表示所有的权限(读、写、查询、删除等等操作), *.*
前面的 *
表示所有的数据库,后面的 *
表示所有的表,identified by 后面跟密码,用单引号括起来。这里的user1指的是localhost上的user1,如果是给网络上的其他机器上的某个用户授权则这样:
mysql> grant all on db1.* to 'user2'@'10.0.2.100' identified by '111222'; Query OK, 0 rows affected (0.01 sec)
用户和主机的IP之间有一个@,另外主机IP那里可以用%替代,表示所有主机,例如:
mysql> grant all on db1.* to 'user3'@'%' identified by '231222'; Query OK, 0 rows affected (0.00 sec)
MySQL数据库的备份与恢复
备份:
[root@winner ~]# mysqldump -uroot -p'root' mysql >/tmp/mysql.sql 不是在mysql>环境
使用 mysqldump 命令备份数据库,-u 和 -p 两个选项使用方法和前面说的 mysql 同样,而后面的 “mysql” 指的是库名,然后重定向到一个文本文档里。备份完后,你可以查看 /tmp/mysql.sql 这个文件里的内容。
恢复和备份正好相反:
[root@localhost ~]# mysql -uroot -p'yourpassword' mysql </tmp/mysql.sql