1 - 数据库服务概述 | 构建MySQL服务 | 数据库基本管理

数据库服务概述 | 构建MySQL服务 | 数据库基本管理 | MySQL基本类型

数据库服务概述
构建mysql服务
- 安装mysql软件包
- 连接mysql服务器修改密码
密码管理
安装图形软件
必备命令
相关参数
基础查询

数据库服务概述

数据库就是存储数据的仓库
用来存储数据的服务器就成为数据库服务器
在这里插入图片描述

构建mysql服务

如果之前有mariadb，则需要先卸载，并删除对应的配置与数据：

[root@host50 ~]# systemctl  stop mariadb

删除/etc/my.cnf配置文件
此配置文件由RHEL自带的mariadb-libs库提供：

[root@host50 ~]# rm -rf /etc/my.cnf

删除数据

[root@host50 ~]# rm -rf /var/lib/mysql/*

卸载软件包

[root@host50 ~]# rpm -e --nodeps mariadb-server  mariadb 
警告：/var/log/mariadb/mariadb.log 已另存为/var/log/mariadb/mariadb.log.rpmsave

安装mysql软件包

解压mysql-5.7.17.tar 软件包

[root@host50 ~]# tar -xvf mysql-5.7.17.tar               //解压mysql整合包

安装MySQL软件包

[root@host50 ~]# yum  -y   install    mysql-community-*.rpm   //yum安装自动解决依赖

启动MySQL数据库服务并设置开机自启(提示：第一次启动，需要初始化数据，会比较慢)

[root@host50 ~]# systemctl start mysqld                  //启动mysql服务
[root@host50 ~]# systemctl enable mysqld                 //设置开机自启
[root@host50 ~]# systemctl status mysqld                 //查看mysql服务状态
● mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: active (running) since 二 2018-08-28 10:03:24 CST; 8min ago
     Docs: man:mysqld(8)
           http://dev.mysql.com/doc/refman/en/using-systemd.html
 Main PID: 4284 (mysqld)
   CGroup: /system.slice/mysqld.service
           └─4284 /usr/sbin/mysqld --daemonize --pid-file=/var/r...
8月 28 10:02:56 localhost.localdomain systemd[1]: Starting MySQ...
8月 28 10:03:24 localhost.localdomain systemd[1]: Started MySQL...
Hint: Some lines were ellipsized, use -l to show in full.

[root@host50 ~]# netstat -utnlp | grep 3306

连接mysql服务器修改密码

查看初始密码

[root@host50 ~]#grep -i  'password' /var/log/mysqld.log
2017-04-01T18:10:42.948679Z 1 [Note] A temporary password is generated for root@localhost: mtoa>Av<p6Yk        //随机生成的管理密码为mtoa>Av<p6Yk

使用初始密码连接mysql服务

[root@host50 ~]# mysql -u root -p'mtoa>Av<p6Yk' //初始密码登录
...
mysql>                                     //登录成功后，进入SQL操作环境
...

重置数据库管理员root本机登陆密码

mysql> show database;
mysql> alter user root@"localhost" identified by "123qqq...A";  // 修改密码
Query OK, 0 rows affected (0.00 sec)
mysql> exit;

mysql> show  databases; //查看数据库（看到默认的4个库）
+--------------------+
| Database            |
+--------------------+
| information_schema |
| mysql                |
| performance_schema  |
| sys                |
+--------------------+
4 rows in set (0.00 sec)
mysql> exit   //断开连接

密码管理

修改密码策略（设置密码复杂度）
破解线下服务器root密码
破解线上服务器root密码
修改服务器root密码

修改密码策略（需要登陆）

[root@host50 ~]# mysql -uroot -p123qqq...A
mysql> show variables like "validata_password_%";  //查看与密码相关的全局变量 
+--------------------------------------+--------+
| Variable_name                        | Value  |
+--------------------------------------+--------+
| validate_password_check_user_name    | OFF    |
| validate_password_dictionary_file    |        |
| validate_password_length             | 8      |    //默认密码长度
| validate_password_mixed_case_count   | 1      |
| validate_password_number_count       | 1      |
| validate_password_policy             | MEDIUM |   //默认密码策略
| validate_password_special_char_count | 1      |
+--------------------------------------+--------+
7 rows in set (0.00 sec)

mysql> set global validate_password_length = 6;  //修改密码最小长度
Query OK, 0 rows affected (0.00 sec)

mysql> set global validate_password_policy = 0 ;  //修改密码策略等级为0
Query OK, 0 rows affected (0.00 sec)

mysql> alter user  root@"localhost" identified by "123456";  //修改root密码
Query OK, 0 rows affected (0.03 sec)
mysql> exit; 断开连接

永久配置，修改配置文件

扫描二维码关注公众号，回复： 17350620 查看本文章

[root@host50 ~]# vim /etc/my.cnf
[mysqld]
validate_password_length = 6   //密码最小长度
validate_password_policy = 0   //密码等级

[root@host50 ~]# systemctl  restart mysqld   //重启服务
[root@host50 ~]# mysql -uroot -p123456  //登录
mysql> show variavles like "validate_password_length"; //只查看密码长度
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| validate_password_length | 6     |
+--------------------------+-------+
1 row in set (0.00 sec)
mysql>  show variables like "validate_password_policy"; //只查看密码策略
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| validate_password_policy | LOW   |
+--------------------------+-------+
1 row in set (0.00 sec)

破解数据库管理员root密码（数据库服务处于运行状态但是root忘记了密码）

破解线下数据库服务器管理员root密码

1）修改运行参数并重启服务
如果修改了密码策略必须恢复为默认的默默策略，不然服务无法跳过授权表启动

[root@host50 ~]# vim /etc/my.cnf
[mysqld]
skip-grant-tables  #逃过授权表
#validate_password_length = 6   //注释掉
#validate_password_policy = 0   //注释掉
[root@host50 ~]# systemctl  restart mysqld    //重启服务

无密码登录

[root@host50 ~]# mysql    //无密码登录
mysql> update mysql.user set  authentication_string=password("123qqq...A")
    -> where user="root" and host="localhost";  //修改root用户本机登录密码(要符合默认的密码策略)
Query OK, 1 row affected, 1 warning (0.05 sec)
mysql> flush privileges;  //让修改生效
Query OK, 0 rows affected (0.02 sec)

3）修改配置文件并重启服务

[root@host50 ~]#  vim  /etc/my.cnf
[mysqld]
#skip-grant-tables   //注释
validate_password_length = 6  //删除注释
validate_password_policy = 0  //删除注释

[root@host50 ~]# systemctl  restart mysqld

4）修改后的密码登录

[root@host50 ~]# mysql -uroot -p123qqq...A   //登录
# 如果觉得破解后的密码太复杂，也可以用alter user设置简单的密码

破解线上服务器root密码（线上服务器不允许随便重启）

1）拷贝管理员能正常登录的数据库服务器的MySQL库覆盖本机的mysql库
把host51主机的mysql库拷贝给host50主机

[root@host50 ~]# scp -r [email protected]:/var/lib/mysql/mysql /var/lib/mysql/
[email protected]'s password:  输入登录51主机的密码

2)重新加载数据

[root@host50 ~]# which  pstree  || yum -y install psmisc   安装pstree命令软件 可以查看父进程 
/usr/bin/pstree
[root@host50 ~]# pstree -p | grep   mysqld  | head  -1   查看父进程pid号
           |-mysqld(20261)-+-{
    
    mysqld}(20262)
[root@host50 ~]# kill  -SIGHUP 20261    发送信号给进程 重新加载

3)使用和host51主机一样的密码连接服务

[root@host50 ~]# mysql -uroot -pNSD123...a    密码登录
mysql>

修改root密码

为了数据库管理员root用户密码安全，可以定期修改密码（比如每隔10天修改一次密码）
注意：修改密码必须要知道旧密码才能修改新密码
使用 alter user命令也可以修改登陆密码，这个命令前提是数据库管理员能够登陆服务才能修改

[root@host50 ~]# mysqladmin  -uroot -pNSD123...a  password "123qqq...A"

# 第二种方式

[root@host50 ~]# mysqladmin  -uroot  -p   password 
Enter password: 旧密码
New password: 新密码
Confirm new password: 再输入一遍新密码

安装图形软件

安装phpmyadmin软件
在50主机做如下配置：
1）部署phpmyadmin 运行环境LAP （A指的是apache P指的是php）

[root@host50 ~]# yum -y install httpd  php  php-mysql  安装软件
[root@host50 ~]# systemctl start httpd  启动服务
[root@host50 ~]# systemctl enable httpd 开机运行

2）安装phpmyadmin软件

[root@host50 ~]# tar -zxvf  phpMyAdmin-2.11.11-all-languages.tar.gz  解压软件
[root@host50 ~]# mv phpMyAdmin-2.11.11-all-languages /var/www/html/phpmyadmin  移动并改名

修改配置文件

[root@host50 ~]# cd /var/www/html/phpmyadmin/   进入安装目录
[root@host50 phpmyadmin]# cp config.sample.inc.php config.inc.php  # 拷贝模板文件，生成主配置文件config.inc.php  
[root@host50 phpmyadmin]# vim +17 config.inc.php 只需要修改第17行
$cfg['blowfish_secret'] = 'sww123';  随便添点字符就可以

4）打开真机浏览器，地址栏输入网址 http://192.168.4.50/phpmyadmin
在这里插入图片描述

必备命令

sql> select version(); //查看版本
sql> select user(); //查看登陆用户
sql> select database(); // 查看当前所在的库
sql> show databases; // 查看已有的库
sql> use 库名; //切换库
sql> show table; // 查看一有的表

基础查询

查询格式

select 字段名列表 from 库名.表名; # 查找表里的所有数据
select 字段名列表 from 库名.表名 where 查询条件;  # 只查询与条件匹配的数据

别名拼接去重

//别名
mysql> select name as 姓名 , homedir  家目录 from  tarena.user;
+-----------------+--------------------+
| 姓名            | 家目录             |
+-----------------+--------------------+
| root            | /root              |
| bin             | /bin               |
| daemon          | /sbin              |
| adm             | /var/adm           |
| lp              | /var/spool/lpd     |

//拼接
mysql> select concat(name, "-" , uid ) from tarena.user;
+--------------------------+
| concat(name, "-" , uid ) |
+--------------------------+
| root-0                   |
| bin-1                    |
| daemon-2                 |
| adm-3                    |
| lp-4                     |
| sync-5                   |

//去重
mysql> select distinct gid from tarena.user;
+-------+
| gid   |
+-------+
|     0 |
|     1 |
|     2 |
|     4 |

数值比较的使用

// 查看uid号和号相等的用户、UID、gid号
mysql> select name ,uid,gid from tarena.user where uid = gid ;
+-----------------+-------+-------+
| name            | uid   | gid   |
+-----------------+-------+-------+
| root            |     0 |     0 |
| bin             |     1 |     1 |
| daemon          |     2 |     2 |
| nobody          |    99 |    99 |
| systemd-network |   192 |   192 |
| dbus            |    81 |    81 |

//查看uid号不等与gid号的用户名、UID号、gid号
mysql> select name ,uid,gid from tarena.user where uid != gid ;
+----------+------+------+
| name     | uid  | gid  |
+----------+------+------+
| adm      |    3 |    4 |
| lp       |    4 |    7 |
| sync     |    5 |    0 |
| shutdown |    6 |    0 |
| halt     |    7 |    0 |
| mail     |    8 |   12 |

//查看表记录的前5行
mysql> select  * from  tarena.user where  id <= 5;  
+----+--------+----------+------+------+---------+----------------+---------------+
| id | name   | password | uid  | gid  | comment | homedir        | shell         |
+----+--------+----------+------+------+---------+----------------+---------------+
|  1 | root   | x        |    0 |    0 | root    | /root          | /bin/bash     |
|  2 | bin    | x        |    1 |    1 | bin     | /bin           | /sbin/nologin |
|  3 | daemon | x        |    2 |    2 | daemon  | /sbin          | /sbin/nologin |
|  4 | adm    | x        |    3 |    4 | adm     | /var/adm       | /sbin/nologin |
|  5 | lp     | x        |    4 |    7 | lp      | /var/spool/lpd | /sbin/nologin |
+----+--------+----------+------+------+---------+----------------+---------------+
5 rows in set (0.01 sec)

字符比较的使用

//查找名字叫apache的用户
mysql> select name from tarena.user where name="apache"; 
+--------+
| name   |
+--------+
| apache |
+--------+

//查看shell是/bin/bash的用户
mysql> select name , shell from tarena.user 
where shell = "/bin/bash" ;
+------+-----------+
| name | shell     |
+------+-----------+
| root | /bin/bash |
| plj  | /bin/bash |
+------+-----------+

mysql> select name , uid from tarena.user where uid is null ; 
+------+------+
| name | uid  |
+------+------+
| bob  | NULL |
+------+------+
1 row in set (0.00 sec)

//零个字符
mysql> select name , comment from tarena.user where comment="" ; 
+---------+---------+
| name    | comment |
+---------+---------+
| postfix |         |
| chrony  |         |
| plj     |         |
+---------+---------+
3 rows in set (0.00 sec)

范围匹配的使用

//查看uid号是1或3或5或7的记录
mysql> select name,uid,shell from tarena.user where uid in  (1,3,5,7); 
+------+------+---------------+
| name | uid  | shell         |
+------+------+---------------+
| bin  |    1 | /sbin/nologin |
| adm  |    3 | /sbin/nologin |
| sync |    5 | /bin/sync     |
| halt |    7 | /sbin/halt    |
+------+------+---------------+
4 rows in set (0.01 sec)

//查看shell不是/bin/bash 或 /sbin/nologin的用户
mysql> select name,uid,shell from tarena.user where shell not in  ("/bin/bash","/sbin/nologin"); 
+----------+------+----------------+
| name     | uid  | shell          |
+----------+------+----------------+
| sync     |    5 | /bin/sync      |
| shutdown |    6 | /sbin/shutdown |
| halt     |    7 | /sbin/halt     |
| mysql    |   27 | /bin/false     |
+----------+------+----------------+
4 rows in set (0.00 sec)

//查看uid 在10到30之间的记录，包括10和30本身
mysql> select name , uid , gid  from tarena.user where uid between 10 and 30 ;
+----------+------+------+
| name     | uid  | gid  |
+----------+------+------+
| operator |   11 |    0 |
| games    |   12 |  100 |
| ftp      |   14 |   50 |
| rpcuser  |   29 |   29 |
| mysql    |   27 |   27 |
+----------+------+------+
5 rows in set (0.00 sec)

模糊匹配的使用

//查看名字是3个字符的
mysql> select name from tarena.user where name like "___";
+------+
| name |
+------+
| bin  |
| adm  |
| ftp  |
| rpc  |
| plj  |
| bob  |
+------+
6 rows in set (0.00 sec)

//查看名字至少是4个字符的 
mysql> select name from tarena.user where name like "__%__"; 
+-----------------+
| name            |
+-----------------+
| root            |
| daemon          |
| sync            |
| shutdown        |
| halt            |
| mail            |
| operator        |
| games           |
| nobody          |
| systemd-network |
| dbus            |
| polkitd         |
| sshd            |
| postfix         |

//查看名字里有字母a的
mysql> select name from tarena.user where name like "%a%"; 
+----------+
| name     |
+----------+
| daemon   |
| adm      |
| halt     |
| mail     |
| operator |
| games    |
| haproxy  |
| apache   |
+----------+
8 rows in set (0.00 sec)

正则匹配的使用

// 查看名字必须是r开头且是t结尾的名字
mysql> select name from tarena.user where name regexp "^r.*t$";
+------+
| name |
+------+
| root |
+------+
1 row in set (0.00 sec)

//看名字以数字开头的
mysql> select name from tarena.user where name regexp "^[0-9]"; 
Empty set (0.00 sec)

逻辑比较的使用

//查看名字叫mysql 或者uid 是 0 的 记录
mysql> select name , uid from tarena.user where name = "mysql"  or uid = 0 ;  
+-------+------+
| name  | uid  |
+-------+------+
| root  |    0 |
| mysql |   27 |
+-------+------+
2 rows in set (0.00 sec)

// 既有and又有or  优先匹配and
mysql> select name , uid from tarena.user where name = "root" or name = "bin" and uid = 1 ; 
+------+------+
| name | uid  |
+------+------+
| root |    0 |
| bin  |    1 |
+------+------+
2 rows in set (0.00 sec)

// () 先匹配or 再匹配and
mysql> select name , uid from tarena.user where (name = "root" or name = "bin") and uid = 1 ;  
+------+------+
| name | uid  |
+------+------+
| bin  |    1 |
+------+------+
1 row in set (0.00 sec)