yum安装mysql、数据库tab自动补全，快来浅了解下？

centos7上面没有mysql，它的数据库名字叫做mariadb

[root@localhost ~]#yum install mariadb-server -y
[root@localhost ~]#systemctl start  mariadb.service 
[root@localhost ~]#systemctl stop firewalld
[root@localhost ~]#setenforce 0
[root@localhost ~]#ss -natp |grep 3306    #数据库端口3306
LISTEN     0      50           *:3306                     *:*                   users:(("mysqld",pid=2478,fd=14))
[root@localhost ~]#mysql
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 2
Server version: 5.5.68-MariaDB MariaDB Server

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>
[root@localhost ~]#mysql_secure_installation  #初始化设置  先输入密码 一路回车

mariadb一般不使用

一、使用yum安装mysql

手写配置文件官方源，5.7.3版本，有初始的随机密码

tee /etc/yum.repos.d/mysql.repo <<EOF
[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/x86_64/
enabled=1
gpgcheck=0
EOF


cat >/etc/yum.repos.d/mysql.repo <<EOF
[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/x86_64/
enabled=1
gpgcheck=0
EOF

[root@localhost ~]#cat >/etc/yum.repos.d/mysql.repo <<EOF
> [mysql57-community]
> name=MySQL 5.7 Community Server
> baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/x86_64/
> enabled=1
> gpgcheck=0
> EOF              
#多行重定向写mysql.repo配置官网mysql的yum源
[root@localhost ~]#systemctl stop firewalld
[root@localhost ~]#setenforce 0
setenforce: SELinux is disabled
[root@localhost ~]#yum -y install mysql-community-server  
#安装mysql数据库
[root@localhost ~]#systemctl start mysqld
[root@localhost ~]#ss -natp|grep 3306
LISTEN     0      80          :::3306                    :::*                   users:(("mysqld",pid=40798,fd=21))
[root@localhost ~]#
[root@localhost ~]#grep password /var/log/mysqld.log
#在/var/log/mysqld.log日志文件中过滤password关键字查看初始的登录密码，注意无前面的空格
2024-03-13T07:56:54.672419Z 1 [Note] A temporary password is generated for root@localhost: yinYQQZV=9,l
[root@localhost ~]#mysql -uroot -p'yinYQQZV=9,l'
#mysql -uroot -p'查到的随机密码'
#登录数据库，注意密码有特殊符号是使用引号


#修改密码策略
set global validate_password_policy=0;
set global validate_password_length=1;
alter user root@'localhost' identified by 'abc123'; #修改数据库密码

Mysql数据库修改密码：

set global validate_password_policy=0;

set global validate_password_length=1;   #修改密码策略
alter user root@localhost identified  by 'abc123';
#修改用户root@localhost的密码为abc123

注意数据库的mysql语句需要以 ; 结尾才能执行成功
root@localhost和root@10.0.0.1是俩个用户。
quit;   #退出数据库
mysql -uroot -p'abc123'
#使用新密码登录数据库成功，密码修改成功

数据库的创建与使用

①登录数据库后输入 show databases; (注意分号结尾)表示查看所有数据库，如上是默认库截图

②show create database 库名；查看某个库信息，如下查看默认库sys信息

③create database 库名；创建数据库XX，如下创建class库

④ use 库名；进入某个库，如下进入class库

我们看到使用数据库，不能显示当前位置，还没有补全，打错命令还需要重新打，接下来我们就来优化mysql数据库吧

二、安装mycli 插件客户端工具

mycli 和 mysql 都是客户端工具

[root@localhost ~]#hostname zzzcentos2
[root@localhost ~]su
[root@zzzcentos2 ~]#yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel libffi-devel
[root@zzzcentos2 ~]#mkdir /data/
[root@zzzcentos2 ~]#cd /data/
[root@zzzcentos2 data]#ls
[root@zzzcentos2 data]#rz -E
rz waiting to receive.
[root@zzzcentos2 data]#ls
Python-3.7.7_.tgz
[root@zzzcentos2 data]#tar xf Python-3.7.7_.tgz 
[root@zzzcentos2 data]#ls
Python-3.7.7  Python-3.7.7_.tgz
[root@zzzcentos2 data]#cd Python-3.7.7/
[root@zzzcentos2 Python-3.7.7]#./configure --prefix=/usr/local/Python-3.7.7/
[root@zzzcentos2 Python-3.7.7]#yum install gcc -y
[root@zzzcentos2 Python-3.7.7]#./configure --prefix=/usr/local/Python-3.7.7/
[root@zzzcentos2 Python-3.7.7]#make
[root@zzzcentos2 Python-3.7.7]#make install
[root@zzzcentos2 Python-3.7.7]#ln -s  /usr/local/Python-3.7.7/bin/python3.7  /usr/bin/python37
[root@zzzcentos2 Python-3.7.7]#ln -s /usr/local/Python-3.7.7/bin/pip3.7 /usr/bin/pip37
[root@zzzcentos2 Python-3.7.7]#pip37 install mycli -i http://mirrors.aliyun.com/pypi/simple --trusted-host mirrors.aliyun.com
[root@zzzcentos2 Python-3.7.7]#ln -s /usr/local/Python-3.7.7/bin/mycli /usr/bin/mycli
[root@zzzcentos2 Python-3.7.7]#
[root@zzzcentos2 Python-3.7.7]#mycli -uroot -pabc123
Connecting to socket /var/lib/mysql/mysql.sock, owned by user mysql
MySQL 
mycli 1.27.0
Home: http://mycli.net
Bug tracker: https://github.com/dbcli/mycli/issues
Thanks to the contributor - François Pietka
MySQL root@(none):(none)> quit
Goodbye!
[root@zzzcentos2 Python-3.7.7]#