目录
一、构建Linux下MySQL数据库
1、MySQL数据库
MySQL是一个关系型数据库管理系统，由瑞典MySQL AB 公司开发，属于 Oracle 旗下产品。MySQL 是最流行的关系型数据库管理系统之一，关系数据库将数据保存在不同的表中，而不是将所有数据放在一个大仓库内，这样就增加了速度并提高了灵活性。
MySQL两个引擎：MyISAM和innoDB。区别是MyISAM类型的表强调的是性能，其执行速度比InnoDB类型更快，但不提供事务支持，如果执行大量的SELECT操作，MyISAM是更好的选择，支持表锁。InnoDB提供事务支持事务外部键等高级数据库功能，执行大量的INSERT或UPDATE，出于性能方面的考虑，应该使用InnoDB表，支持行锁。
2、MySQL安装
（1）命令行安装(无)
（2）源码下载安装
查了下现在安装方式都是rpm安装，下载路径如下：https://dev.mysql.com/downloads/mysql/
[root@localhost opt]# tar -xvf mysql-8.0.21-1.el7.x86_64.rpm-bundle\ \(1\).tar
mysql-community-common-8.0.21-1.el7.x86_64.rpm
mysql-community-embedded-compat-8.0.21-1.el7.x86_64.rpm
mysql-community-libs-8.0.21-1.el7.x86_64.rpm
mysql-community-devel-8.0.21-1.el7.x86_64.rpm
mysql-community-server-8.0.21-1.el7.x86_64.rpm
mysql-community-client-8.0.21-1.el7.x86_64.rpm
mysql-community-libs-compat-8.0.21-1.el7.x86_64.rpm
mysql-community-test-8.0.21-1.el7.x86_64.rpm
（3）rpm安装
这里主要使用的mysql组件有4个：server、client、common、libs，安装顺序依次为：common→libs→client→server
[root@localhost opt]# rpm -ivh mysql-community-common-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-common-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-common-8.0.21-1.e################################# [100%]
[root@localhost opt]# rpm -ivh mysql-community-libs-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-libs-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-libs-8.0.21-1.el7################################# [100%]
[root@localhost opt]# rpm -ivh mysql-community-client-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-client-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-client-8.0.21-1.e################################# [100%]
[root@localhost opt]# rpm -ivh mysql-community-server-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-server-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing... ################################# [100%]
Updating / installing...
1:mysql-community-server-8.0.21-1.e################################# [100%]
注：
（1）安装lib时候报错，解决方法：yum remove mysql-libs，清除之前的依赖再继续安装
[root@localhost opt]# rpm -ivh mysql-community-libs-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-libs-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
mariadb-libs is obsoleted by mysql-community-libs-8.0.21-1.el7.x86_64
（2）安装server时候报错，需要先安装perl
[root@localhost opt]# rpm -ivh mysql-community-server-8.0.21-1.el7.x86_64.rpm
warning: mysql-community-server-8.0.21-1.el7.x86_64.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
error: Failed dependencies:
/usr/bin/perl is needed by mysql-community-server-8.0.21-1.el7.x86_64
net-tools is needed by mysql-community-server-8.0.21-1.el7.x86_64
perl(Getopt::Long) is needed by mysql-community-server-8.0.21-1.el7.x86_64
wget https://cpan.metacpan.org/authors/id/S/SH/SHAY/perl-5.30.2.tar.gz
tar -zxvf perl-5.30.2.tar.gz -C /opt
./Configure -des -Dprefix=/opt/perl-5.30.2
make && make test
make install
perl -v
yum install net-tools
3、启动mysql服务
systemctl start mysqld.service //启动mysql
systemctl status mysqld.service //查看mysql状态
systemctl stop mysqld.service //关闭mysql
[root@localhost etc]# systemctl start mysqld.service
[root@localhost etc]# systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: active (running) since Sun 2020-10-04 16:39:16 EDT; 28s ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
Process: 18727 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 18800 (mysqld)
Status: "Server is operational"
CGroup: /system.slice/mysqld.service
└─18800 /usr/sbin/mysqld
Oct 04 16:38:55 localhost.localdomain systemd[1]: Starting MySQL Server...
Oct 04 16:39:16 localhost.localdomain systemd[1]: Started MySQL Server.
[root@localhost etc]# systemctl stop mysqld.service
启动后可以通过命令查看服务状态
[root@localhost ~]# ps -ef|grep mysql
mysql 18800 1 1 16:39 ? 00:00:51 /usr/sbin/mysqld
root 19229 18899 0 17:43 pts/1 00:00:00 grep --color=auto mysql
[root@localhost ~]# ps -ef|grep mysqld
mysql 18800 1 1 16:39 ? 00:00:51 /usr/sbin/mysqld
root 19231 18899 0 17:43 pts/1 00:00:00 grep --color=auto mysqld
[root@localhost ~]# netstat -anop|grep 3306
tcp6 0 0 :::33060 :::* LISTEN 18800/mysqld off (0.00/0/0)
tcp6 0 0 :::3306 :::* LISTEN 18800/mysqld off (0.00/0/0)
4、登陆MySQL以及修改root密码
在新版本的mysql中在安装过程中自动设定一个默认密码，这个密码可以通过日志查看，命令如下
[root@localhost ~]# grep 'temporary password' /var/log/mysqld.log
2020-10-04T20:39:03.831989Z 6 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: pp4,WVoe?kOj
这里pp4,WVoe?kOj即为登陆密码，使用这个密码可以登陆，登陆命令如下：
[root@localhost ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.21
Copyright (c) 2000, 2020, 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>
登陆后可以修改密码，首次修改需要按复杂度修改，否则会报错，修改命令如下
mysql> ALTER USER root@localhost IDENTIFIED BY '123456';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements
mysql> ALTER USER root@localhost IDENTIFIED BY '123qweRTY!@#';
Query OK, 0 rows affected (0.05 sec)
修改密码后可以查看密码设置相关参数，命令如下
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+--------+
| Variable_name | Value |
+--------------------------------------+--------+
| validate_password.check_user_name | ON |
| validate_password.dictionary_file | |
| validate_password.length | 8 |
| validate_password.mixed_case_count | 1 |
| validate_password.number_count | 1 |
| validate_password.policy | MEDIUM |
| validate_password.special_char_count | 1 |
+--------------------------------------+--------+
7 rows in set (0.02 sec)
其中密码复杂度和validate_password_policy这个参数有关，参数说明如下表，默认复杂度是1即MEDIUM，所以首次设置密码必须含有数字，小写或大写字母，特殊字符。
| Policy | Tests Performe（要求 |
|---|---|
| 0 or LOW | Length |
| 1 or MEDIUM | numeric, lowercase/uppercase, and special characters |
| 2 or STRONG | Length; numeric, lowercase/uppercase, and special characters |
首次修改密码后可以修改密码默认配置，便于设置一个简单的密码
mysql> set global validate_password.policy=0;
Query OK, 0 rows affected (0.01 sec)
mysql> set global validate_password.length=1;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'validate_password%';
+--------------------------------------+-------+
| Variable_name | Value |
+--------------------------------------+-------+
| validate_password.check_user_name | ON |
| validate_password.dictionary_file | |
| validate_password.length | 4 |
| validate_password.mixed_case_count | 1 |
| validate_password.number_count | 1 |
| validate_password.policy | LOW |
| validate_password.special_char_count | 1 |
+--------------------------------------+-------+
7 rows in set (0.00 sec)
mysql> ALTER USER root@localhost IDENTIFIED BY '1234';
Query OK, 0 rows affected (0.06 sec)
5、简单SQL操作
mysql> create database test_db;
Query OK, 1 row affected (0.05 sec)
mysql> use test_db;
Database changed
mysql> show tables;
Empty set (0.01 sec)
mysql> create table test01(id varchar(20),name varchar(20));
Query OK, 0 rows affected (0.12 sec)
mysql> insert into test01 values("test01", "yangxiaoyang");
Query OK, 1 row affected (0.10 sec)
mysql> select * from test01;
+--------+--------------+
| id | name |
+--------+--------------+
| test01 | yangxiaoyang |
+--------+--------------+
1 row in set (0.00 sec)
mysql> desc test01;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| id | varchar(20) | YES | | NULL | |
| name | varchar(20) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.01 sec)
新用户授予权限，注意mysql8.0以后版本授权方式发生变化，该版本将创建账户和赋予权限分开
mysql> create user 'yang'@'192.168.56.102' identified by '123456';
Query OK, 0 rows affected (0.06 sec)
mysql> grant all privileges on *.* to 'yang'@'192.168.56.102' with grant option;
Query OK, 0 rows affected (0.13 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.07 sec)
MySQL备份与恢复
[root@localhost ~]# mysqldump -uroot -p1234 test_db > test_db.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@localhost ~]# ls
anaconda-ks.cfg data test_db.sql tmp
[root@localhost ~]# mysql -uroot -p1234 test_db < test_db.sql
mysql: [Warning] Using a password on the command line interface can be insecure.参考文档：