Linux之CentOS下yum安装MySQL

用yum安装MySql

1. 打入如下命令：
   1. [root@mysql ~]# yum -y install mysql-server      //自动从网上搜索资源并自动下载安装
2. [root@mysql ~]# chkconfig mysqld on    //设置开机启动MySql服务
   1. 检查是否为开机启动
   2. 打入命令：[root@mysql ~]# chkconfig –list
   3. 看到：mysqld          0:off   1:off   2:on    3:on    4:on    5:on    6:off 即表示已设置为开机启动，2、3、4、5为on
3. 启动MySql服务
   1.  /etc/rc.d/init.d/mysqld start   //从文件启动MySql服务
   2. service mysqld start            //以服务名方式启动

 

MySql初始化环境设置（一）

1. 设置MySQL的root用户设置密码，因为MySQL被安装时，它的root用户时没有设置密码的。

–      [root@mysql ~]# mysql -u root

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 2

Server version: 5.1.61 Source distribution

Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its

affiliates. Other names may be trademarks of their respective

owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

2.       如上，默认是不需要密码就可以进入数据库操作，下面查看MySQL数据库用户信息

 

 

MySql初始化环境设置（二）

1. 打入命令：select user,host,password from mysql.user; //可以看到密码都为空

–      +------+-----------+----------+

–      | user | host      | password |

–      +------+-----------+----------+

–      | root | localhost |          |

–      | root | mysql     |          |

–      | root | 127.0.0.1 |          |

–      |      | localhost |          |

–      |      | mysql     |          |

–      +------+-----------+----------+

–      5 rows in set (0.00 sec)

–      set password for root@localhost=password(‘123456789’); //设置root用户密码为123456789

 

 

MySql初始化环境设置（三）

•       打入命令：select user,host,password from mysql.user; //查看刚设置的密码，可以看到密码已经经过加密处理

–      +------+-----------+-------------------------------------------+

–      | user | host      | password                                  |

–      +------+-----------+-------------------------------------------+

–      | root | localhost | *CC67043C7BCFF5EEA5566BD9B1F3C74FD9A5CF5D |

–      | root | mysql     |                                           |

–      | root | 127.0.0.1 |                                           |

–      |      | localhost |                                           |

–      |      | mysql     |                                           |

–      +------+-----------+-------------------------------------------+

–      5 rows in set (0.00 sec)

•       打入exit命令退出数据库连接，测试root密码是否生效

 

 

MySql初始化环境设置（四）

•       打入命令：mysql –u root

–      ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mysql -u root' at line 1

–      弹出图上提示说明刚设置的密码已生效

•       下面通过密码登陆，打入命令：mysql –u root –p //在Enter password后输入刚才设置的密码，看到下面即表示登陆成功

–      [root@mysql ~]# mysql -u root -p

–      Enter password:

–      Welcome to the MySQL monitor. Commands end with ; or \g.

–      Your MySQL connection id is 3

–      Server version: 5.1.61 Source distribution

–      Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

–      Oracle is a registered trademark of Oracle Corporation and/or its

–      affiliates. Other names may be trademarks of their respective

–      owners.

–      Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

–      mysql>

 

 

增删改查语句

•       Show databases; //查看系统已存在的数据库

•       use databasesname;   //选择需要使用的数据库

•       drop database databasename; //删除选定的数据库

•       exit    //退出数据库的连接

•       create database test01;    //建立名为test的数据库

–      mysql> show databases;

–      +--------------------+

–      | Database           |

–      +--------------------+

–      | information_schema |

–      | mysql              |

–      | test               |

–      | test01             |

–      +--------------------+

–      4 rows in set (0.00 sec)

•        可以看到新建的test01数据库

•       use test01;      //连接到数据库test01

–      mysql> use test01;

–      Database changed

•       mysql> create talbe test(num int,name varchar(50)); //在数据库中建立表

–      mysql> create table test(num int,name varchar(50));

–      Query OK, 0 rows affected (0.11 sec)

•       mysql> insert into test values(1,’Hello World!’) ;   //插入一个值到表中

–      mysql> create table test(num int,name varchar(50));

–      Query OK, 0 rows affected (0.11 sec)

•       select * from test;   //查看数据库中表的信息

–       mysql> select * from test;

–      +------+--------------+

–      | num | name         |

–      +------+--------------+

–      |    1 | Hello World! |

–      +------+--------------+

–      1 row in set (0.00 sec)