卸载mysql

1、首先查看mysql的安装情况

rpm -qa|grep mysql

2、停止mysql服务,并删除包

rpm -ev mysql-community-client-8.0.26-1.el7.x86_64 --nodeps rpm -ev mysql-community-server-8.0.26-1.el7.x86_64 mysql-community-libs-8.0.26-1.el7.x86_64 mysql-community-common-8.0.26-1.el7.x86_64 --nodeps

3、查找之前老版本mysql的目录、并且删除老版本mysql的文件和库

[root@lYIK5tHp ~]# find / -name mysql /root/tempfiles/leanote/bin/src//revel/modules/auth/driver/storage/mysql /var/lib/mysql /var/lib/mysql/mysql /usr/local/mysql [root@lYIK5tHp ~]# rm -rf /var/lib/mysql /var/lib/mysql/mysql /usr/local/mysql/

注意：卸载后/etc/my.cnf不会删除，需要进行手工删除

rm -rf /etc/my.cnf

4、再次查询再次查找机器是否安装mysql

rpm -qa|grep -i mysql

无结果，说明已经卸载彻底

安装mysql

在CentOS中默认安装有MariaDB，这个是MySQL的分支，但为了需要，还是要在系统中安装MySQL，而且安装完成之后可以直接覆盖掉MariaDB

1、官网下载压缩包，上传linux

官网

下载之后，通过ssh工具sftp/ftp方式上传到你服务器centos7指定的目录即可/usr/local/

1、解压并且移动usr/local

tar -Jxvf mysql-8.0.27-linux-glibc2.17-x86_64-minimal.tar.xz mv mysql-8.0.27-linux-glibc2.17-x86_64-minimal /usr/local cd /usr/local mv mysql-8.0.27-linux-glibc2.17-x86_64-minimal mysql

2、创建 用户，并给数据目录赋予权限

进入/usr/local/mysql目录下，创建data文件夹，并授权

# 创建用户组 groupadd mysql # 创建mysql用户 useradd -g mysql mysql # 切换mysql目录 cd /usr/local/mysql/ # 创建数据库文件夹 mkdir data # 给mysql文件夹授权 chown -R root:root /usr/local/mysql # 给mysql文件夹授权 chown -R mysql:mysql /usr/local/mysql/data/

3、初始化数据库，并会自动生成随机密码，记下等下登陆要用

# 初始化数据库，mysql的bin目录下的mysqld命令 /usr/local/mysql/bin/mysqld --initialize --user=mysql --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data

临时密码：root@localhost:后面的那串代码

4、cp /usr/local/mysql/support-files/my-default.cnf /etc/my.cnf

复制过去，其实也就是空白页，一开始没有my-default.cnf这个文件，可以用touch my-default.cnf命令创建一个，并配置权限

chmod 777 ./my-default.cnf

5、配置my.cnf

vim /etc/my.cnf

my.cnf

[mysqld] # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin # These are commonly set, remove the # and set as required. basedir = /usr/local/mysql datadir = /usr/local/mysql/data socket = /tmp/mysql.sock log-error = /usr/local/mysql8/data/error.log pid-file = /usr/local/mysql8/data/mysql.pid port = 3306 #lower_case_table_names = 1 # server_id = ..... # socket = ..... #lower_case_table_names = 1 max_allowed_packet=32M default-authentication-plugin = mysql_native_password #lower_case_file_system = on #lower_case_table_names = 1 log_bin_trust_function_creators = ON # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

6、开机自启，进入/usr/local/mysql/support-files进行设置

cd support-files/ cp mysql.server /etc/init.d/mysql chmod +x /etc/init.d/mysql

7、注册服务并检测

# 添加到系统服务 chkconfig --add mysql # 检查服务是否生效 chkconfig --list mysql

8、配置全局环境变量

# 配置环境变量 vim /etc/profile # 添加如下内容： # MYSQL ENVIRONMENT export PATH=$PATH:/usr/local/mysql/bin:/usr/local/mysql/lib # 系统重新加载文件，记得一定要 source /etc/profile

9、启动MySQL服务并且登录MySQL

# 启动mysql服务 service mysql start # 关闭mysql服务 service mysql stop # 重启mysql服务 service mysql restart

10、修改密码和远程登录

修改默认密码

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'root';

开启远程连接

平时我们一般使用可视化工具访问mysql，例如Navicat，这就需要输入ip访问，需要设置远程访问权限,执行如下操作

# 切换数据库 use mysql ; # 查看用户表 select user , host from user ; # 更新所有用户可以访问 update user set host = '%' where user = 'root' ; # 刷新权限 flush privileges ;

云服务器开启端口

若是阿里云服务器需要开启3306端口，找到云服务器工作台，在网络与安全栏目打开安全组

可视化工具连接数据库

通过dbeaver连接，操作步骤如下

1、空白区域右键=》创建=》连接，

2、指定数据库类型，比如mysql，oracle等

3、连接配置参数说明

4、成功连接