卸载MariaDB

1.检查

rpm -qa|grep mariadb
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2.卸载

rpm -e --nodeps mariadb-libs-5.5.56-2.el7.x86_64
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3.检查是否卸载干净

rpm -qa|grep mariadb
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安装MySQL

1.两种方法安装

• 官网手动下载安装

官网地址：https://dev.mysql.com/downloads/mysql/
下载好后拖动到Linux的/usr/local
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• 网络安装

cd /usr/local
wget https://dev.mysql.com/get/Downloads/MySQL-8.0/mysql-8.0.20-linux-glibc2.12-x86_64.tar.xz
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2.解压

.tar.gz后缀：tar -zxvf 文件名
.tar.xz后缀：tar -Jxvf 文件名
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3.重命名

mv 原文件夹名 mysql8
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4.配置环境变量

• vim /etc/profile

JAVA_HOME=/usr/java/jdk1.8.0_152
JRE_HOME=/usr/java/jdk1.8.0_151/jre
HADOOP_HOME=/usr/local/hadoop-2.7.1
ZOOKEEPER_HOME=/usr/local/zookeeper-3.3.6
FLUME_HOME=/usr/local/flume-1.9.0
NGINX_HOME=/usr/local/nginx
TOMCAT_HOME=/usr/local/tomcat-8.5.81
MYSQL8_HOME=/usr/local/mysql8

CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin:$HADOOP_HOME/bin:$HADOOP_HOME/sbin:$ZOOKEEPER_HOME/bin:$FLUME_HOME/bin:$NGINX_HOME/sbin:$TOMCAT_HOME/bin:$MYSQL8_HOME/bin
export PATH CLASSPATH JAVA_HOME JRE_HOME HADOOP_HOME ZOOKEEPER_HOME FLUME_HOME NGINX_HOME TOMCAT_HOME MYSQL8_HOME
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• source /etc/profile

5.用户和用户组

• 创建一个用户组：mysql

groupadd mysql
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• 创建一个系统用户：mysql，指定用户组为mysql

useradd -r -g mysql mysql
	-r：创建系统用户
	-g：指定用户组
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6.数据目录

• 创建目录

cd /usr/local/mysql8
mkdir datas
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• 更改属主和数组

chown -R mysql:mysql /usr/local/mysql8/datas
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• 更改模式

chmod -R 750 /usr/local/mysql8/datas
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初始化MySQL

1.配置参数

• cd /usr/local/mysql8
• vim my.cnf

[mysql]
# 默认字符集
default-character-set=utf8mb4
[client]
port       = 3306
socket     = /tmp/mysql.sock

[mysqld]
port       = 3306
server-id  = 3306
user       = mysql
socket     = /tmp/mysql.sock
# 安装目录
basedir    = /usr/local/mysql8
# 数据存放目录
datadir    = /usr/local/mysql8/datas/mysql
log-bin    = /usr/local/mysql8/datas/mysql/mysql-bin
innodb_data_home_dir      =/usr/local/mysql8/datas/mysql
innodb_log_group_home_dir =/usr/local/mysql8/datas/mysql
#日志及进程数据的存放目录
log-error =/usr/local/mysql8/datas/mysql/mysql.log
pid-file  =/usr/local/mysql8/datas/mysql/mysql.pid
# 服务端使用的字符集默认为8比特编码
character-set-server=utf8mb4
lower_case_table_names=1
autocommit =1
 
 ##################以上要修改的########################
skip-external-locking
key_buffer_size = 256M
max_allowed_packet = 1M
table_open_cache = 1024
sort_buffer_size = 4M
net_buffer_length = 8K
read_buffer_size = 4M
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 64M
thread_cache_size = 128
  
#query_cache_size = 128M
tmp_table_size = 128M
explicit_defaults_for_timestamp = true
max_connections = 500
max_connect_errors = 100
open_files_limit = 65535
   
binlog_format=mixed
    
binlog_expire_logs_seconds =864000
    
# 创建新表时将使用的默认存储引擎
default_storage_engine = InnoDB
innodb_data_file_path = ibdata1:10M:autoextend
innodb_buffer_pool_size = 1024M
innodb_log_file_size = 256M
innodb_log_buffer_size = 8M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50
transaction-isolation=READ-COMMITTED
      
[mysqldump]
quick
max_allowed_packet = 16M
       
[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 4M
read_buffer = 2M
write_buffer = 2M
        
[mysqlhotcopy]
interactive-timeout
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2.初始化

• mysqld --defaults-file=/usr/local/mysql8/my.cnf --basedir=/usr/local/mysql8/ --datadir=/usr/local/mysql8/datas/mysql --user=mysql --initialize-insecure

defaults-file：指定配置文件（要放在–initialize 前面）
user： 指定用户
basedir：指定安装目录
datadir：指定初始化数据目录
intialize-insecure：初始化无密码
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启动MySQL

1.查看 MySQL的 bin路径下，是否包含mysqld_safe

2.启动服务

• 完整命令

/usr/local/mysql8/bin/mysqld_safe --defaults-file=/usr/local/mysql8/my.cnf &
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• 加上环境变量后的命令

mysqld_safe --defaults-file=/usr/local/mysql8/my.cnf &
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3.查看是否启动

• ps -ef|grep mysql
  

登录

1.无密码登录方式

• /usr/local/mysql8/bin/mysql -u root --skip-password
  

2.有密码登录方式（初始的随机密码在/data/mysql8_data/mysql/mysql.log下）

• mysql -u root -p
• password:随机密码

修改密码

1.修改密码

• ALTER USER ‘root’@‘localhost’ IDENTIFIED WITH mysql_native_password
  BY ‘a’;

2.刷新权限

• FLUSH PRIVILEGES;

设置允许远程登录

1.设置

• use mysql
• update user set user.Host='%'where user.User=‘root’;
• flush privileges;
• quit

2.Navicat测试