MySQL的安装、改密及远程连接

一、下载MySQL压缩包后的安装步骤

1. 将压缩包解压到指定的目录
2. 编辑好配置文件

[mysql]
#设置MySQL客户端默认字符集
default-character-set=utf8

[mysqld]
#设置3306端口
port = 3306

#设置MySQL的安装目录
basedir =D:\Program Files\MySQL\mysql-8.0.22-winx64

#设置MySQL数据库的数据的存放目录
datadir = D:\Program Files\MySQL\mysql-8.0.22-winx64\data

#允许最大连接数
max_connections=20

#服务端使用字符集默认为8比特编码的latin1字符集
character-set-server=utf8

#创建新表时将使用的默认存储引擎
default-storage-engine=INNODB

• DOS窗口下输入安装命令
• ①进入到MySQL的bin目录下，或者配置好环境变量即可，任意路径可操作
  输入命令：mysqld install

	C:\WINDOWS\system32>mysqld install
	The service already exists!
	The current server installed:

• 注释：提示该服务已存在，先卸载，命令：mysqld remove

	C:\WINDOWS\system32>mysqld remove
	Service successfully removed.

• ②继续安装

	C:\WINDOWS\system32>mysqld install
	Service successfully installed.

• 注释：提示安装成功
• ③根据配置文件进行初始化命令：mysqld --initialize-insecure

	C:\WINDOWS\system32>mysqld --initialize-insecure

• ④启动MySQL服务，命令：net start mysql

	C:\WINDOWS\system32>net start mysql
	MySQL 服务正在启动 ..
	MySQL 服务已经启动成功。

• ⑤进入MySQL，root账号免密进入，命令：mysql -u root

C:\WINDOWS\system32>mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.22 MySQL Community Server - GPL

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>

• ⑥查看MySQL有几个数据库,起始有4个才正常，查看命令;mysql> show databases;

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

二、DOS命令更改MySQL的root用户的密码

1. 进入mysql库命令：use mysql; 查看表命令：show tables;

	mysql> use mysql;
	Database changed

mysql> show tables;
+----------------------------------------------+
| Tables_in_mysql                              |
+----------------------------------------------+
| columns_priv                                 |
| component                                    |
| db                                           |
| default_roles                                |
| engine_cost                                  |
| func                                         |
| general_log                                  |
| global_grants                                |
| gtid_executed                                |
| help_category                                |
| help_keyword                                 |
| help_relation                                |
| help_topic                                   |
| innodb_index_stats                           |
| innodb_table_stats                           |
| password_history                             |
| plugin                                       |
| procs_priv                                   |
| proxies_priv                                 |
| replication_asynchronous_connection_failover |
| role_edges                                   |
| server_cost                                  |
| servers                                      |
| slave_master_info                            |
| slave_relay_log_info                         |
| slave_worker_info                            |
| slow_log                                     |
| tables_priv                                  |
| time_zone                                    |
| time_zone_leap_second                        |
| time_zone_name                               |
| time_zone_transition                         |
| time_zone_transition_type                    |
| user                                         |
+----------------------------------------------+
34 rows in set (0.00 sec)

2.user表中管理用户名与密码因此我们在这张表里面去修改，命令：
alter user ‘root’ @‘localhost’ identified by ‘123456’;

mysql> alter user 'root' @'localhost' identified by '123456';
Query OK, 0 rows affected (0.15 sec)

3.改完记得重新加载权限表，命令：flush privileges;

mysql> flush privileges;
Query OK, 0 rows affected (0.08 sec)

4.退出mysql重进，命令：mysql -u root

C:\WINDOWS\system32>mysql -u root
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: NO)

• 注释：此刻没有密码是进不去的，证明我们改密成功了

5.输入命令：mysql -u root -p

C:\WINDOWS\system32>mysql -u root -p
Enter password: ******
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 12
Server version: 8.0.22 MySQL Community Server - GPL

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>

• 注释：输入密码成功进入

三、如何使用工具端Navicat连接数据库

1. 打开客户端工具，输入相关的信息，点击测试连接
   
   

• 注释：提示上述错误，是一个关于加密规则的错误：

很多用户在使用Navicat Premium 12连接MySQL数据库时会出现Authentication plugin ‘caching_sha2_password’ cannot be loaded的错误。出现这个原因是mysql 8 之前的版本中加密规则是mysql_native_password,而在mysql 8之后,加密规则是caching_sha2_password, 解决问题方法有两种,一种是升级navicat驱动,一种是把mysql用户登录密码加密规则还原成mysql_native_password.

1. 进入mysql库，在users表里面查看加密规则

mysql> use mysql;
Database changed
mysql> select host,user,plugin from user;
+-----------+------------------+-----------------------+
| host      | user             | plugin                |
+-----------+------------------+-----------------------+
| localhost | mysql.infoschema | caching_sha2_password |
| localhost | mysql.session    | caching_sha2_password |
| localhost | mysql.sys        | caching_sha2_password |
| localhost | root             | caching_sha2_password |
+-----------+------------------+-----------------------+
4 rows in set (0.00 sec)

• host：允许用户登录的 ip，此处如果为 % 表示可以远程；
• user: 当前数据库的用户名；
• plugin： 密码加密方式；
• 在mysql 5.7.9以后废弃了password字段和password()函数

1. 修改加密规则

	mysql> ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '123456';
	Query OK, 0 rows affected (0.10 sec)

	mysql> flush privileges;
	Query OK, 0 rows affected (0.08 sec)

1. 修改加密规则后再次查看

mysql> select host,user,plugin from user;
+-----------+------------------+-----------------------+
| host      | user             | plugin                |
+-----------+------------------+-----------------------+
| localhost | mysql.infoschema | caching_sha2_password |
| localhost | mysql.session    | caching_sha2_password |
| localhost | mysql.sys        | caching_sha2_password |
| localhost | root             | mysql_native_password |
+-----------+------------------+-----------------------+
4 rows in set (0.00 sec)

1. 然后重复一步骤，出现如下错误：
   

2. 在步骤2中就发现不能远程，设置如下：

mysql> update user set Host='%' where User='root';
Query OK, 1 row affected (0.12 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> flush privileges;
Query OK, 0 rows affected (0.08 sec)

1. 再次查看，发现root账号可以远程连接。

mysql> select host,plugin,user from user;
+-----------+-----------------------+------------------+
| host      | plugin                | user             |
+-----------+-----------------------+------------------+
| %         | mysql_native_password | root             |
| localhost | caching_sha2_password | mysql.infoschema |
| localhost | caching_sha2_password | mysql.session    |
| localhost | caching_sha2_password | mysql.sys        |
+-----------+-----------------------+------------------+
4 rows in set (0.01 sec)