MySQL学习（二）-单机版-yum安装

一、环境准备

1.系统环境：CentOS 7.5

[root@localhost software]# cat /etc/redhat-release
CentOS Linux release 7.9.2009 (Core)

2、卸载自带数据库：maridb

# 查询已安装数据库
rpm -qa | grep -i mariadb
# 卸载已安装数据库
rpm -qa | grep mariadb | xargs rpm -e --nodeps

二、安装教程

1.yum respository 下载

wget http://repo.mysql.com//mysql57-community-release-el7-8.noarch.rpm

2.yum respository 安装

yum -y install mysql57-community-release-el7-8.noarch.rpm

3.安装MySQL服务端

# 查找安装包
yum search mysql-com
# 安装MySQL
yum -y install mysql-community-server.x86_64

4.启动MySQL服务

# 启动MySQL服务
systemctl start mysqld.service
# 查看MySQL启动状态
systemctl status mysqld.service

三、MySQL数据库初始设置

1.登录MySQL

# 初始密码查看
cat /var/log/mysqld.log | grep 'password'
# MySQL登录
mysql -uroot -p

2.密码修改

密码修改具体操作

step1： 更改策略，设置 validate_password_policy=0;

mysql> set global validate_password_policy=0;    # 此时，新密码长度大于等于8位才有效，否则报错

修改有效密码长度：

mysql> set global validate_password_length=1;

Query OK, 0 rows affected (0.00 sec)

不管设置  validate_password_length=1,还是2,3,4 ,‘有效密码长度’这个参数的实际值都是4。超过4后设置是多少实际就是多少。

step2：重设密码：

mysql> set password for root@localhost=password('9527');

Query OK, 0 rows affected, 1 warning (0.00 sec)

此时，虽然防火墙我时关着的，但root用户只能用于本机访问，不能用于远程访问，否则会报以下错误。因此，接下来要做的是授予root用户远程访问权限。

3.远程连接

查看当前授予过的权限：

use mysql;
select user,host from user;

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
mysql> select user,host from user;
+---------------+-----------+
| user          | host      |
+---------------+-----------+
| root          | %         |
| mysql.session | localhost |
| mysql.sys     | localhost |
| root          | localhost |
+---------------+-----------+
4 rows in set (0.00 sec)
 
mysql> show grants;
+---------------------------------------------------------------------+
| Grants for root@localhost                                           |
+---------------------------------------------------------------------+
| GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' WITH GRANT OPTION |
| GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION        |
+---------------------------------------------------------------------+
2 rows in set (0.00 sec)

step1: 授予root用户远程访问权限：

mysql> grant all privileges on *.* to root@'%' identified by 'root';
Query OK, 0 rows affected, 1 warning (0.05 sec)

step2: 刷新权限，使设置生效， OK。

mysql> flush privileges;
Query OK, 0 rows affected (0.36 sec)

step3：远程连接测试

以上，请参考！

参考链接一

参考链接二