1-centos7安装mariadb
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centos.7.6 + mariadb5.5.68
说实话，由于平常都是在Linux上使用的是mysql，就没兴趣再继续琢磨怎么安装mariadb了，但老遇到同学问，我就做个笔记。
安装
1. 首先检查是否安装了mariadb，如果有可以选择卸载，也可以选择复用
[root@VM-4-10-centos mariadb]# rpm -qa | grep mariadb
mariadb-server-5.5.68-1.el7.x86_64
mariadb-libs-5.5.68-1.el7.x86_64
mariadb-5.5.68-1.el7.x86_64
这里看到是有的，你也可以直接再使用这个，也可以卸载掉，完事在使用yum安装。
# 卸载命令
[root@VM-4-10-centos mariadb]# rpm -e --nodeps mariadb-server-5.5.68-1.el7.x86_64
[root@VM-4-10-centos mariadb]# rpm -qa | grep mariadb # 卸载完了，在过滤就没了
2. 使用yum进行安装
[root@VM-4-10-centos mariadb]# yum -y install mariadb-server mariadb-client
3. 配置my.cnf
cat > /etc/my.cnf <<EOF
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under a different user or group,
# customize your systemd unit file for mariadb according to the
# instructions in http://fedoraproject.org/wiki/Systemd
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the config directory
#
!includedir /etc/my.cnf.d
EOF
4. 启动mariadb了。
启动服务：systemctl start mariadb.service
停止服务：systemctl stop mariadb.service
查看服务状态：systemctl status mariadb.service
开机启动：systemctl enable mariadb
5. 账号密码设置
默认直接输入mysql就能登录进去，所以，我们要把这个空账号给它干掉，然后设置我们自己的root用户和密码。
[root@VM-4-10-centos mariadb]# mysql # 默认有个空账号，可以让我们初次登录使用
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)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
MariaDB [(none)]> use mysql; -- 先use到mysql数据库下
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
MariaDB [mysql]> select user, password, host from user; -- 看下当前可用的用户，那几个user为空的就是我们需要去掉的
+------+----------+----------------+
| user | password | host |
+------+----------+----------------+
| root | | localhost |
| root | | vm-4-10-centos |
| root | | 127.0.0.1 |
| root | | ::1 |
| | | localhost |
| | | vm-4-10-centos |
+------+----------+----------------+
6 rows in set (0.00 sec)
MariaDB [mysql]> delete from user where user = ''; -- 将为空的删掉
Query OK, 2 rows affected (0.00 sec)
MariaDB [mysql]> select user, password, host from user; -- ok,删掉了
+------+----------+----------------+
| user | password | host |
+------+----------+----------------+
| root | | localhost |
| root | | vm-4-10-centos |
| root | | 127.0.0.1 |
| root | | ::1 |
+------+----------+----------------+
4 rows in set (0.00 sec)
MariaDB [mysql]> -- 将与主机名相等的字段改为 "%",当用户从客户端请求登陆时，MySQL将授权表中的条目与客户端所提供的条目进行比较，包括用户的用户名，密码和主机
MariaDB [mysql]> update user set host='%' where host='vm-4-10-centos'; -- 我的主机名叫做vm-4-10-centos
Query OK, 1 row affected (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 0
MariaDB [mysql]> -- 设置root账号的密码为123
MariaDB [mysql]> update user set password=password('123') where user='root' ;
Query OK, 4 rows affected (0.00 sec)
Rows matched: 4 Changed: 4 Warnings: 0
MariaDB [mysql]> -- 刷新
MariaDB [mysql]> flush privileges;
Query OK, 0 rows affected (0.00 sec)
MariaDB [mysql]> exit;
Bye
[root@VM-4-10-centos mariadb]# mysql -uroot -p123
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 5
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)]>
摘自：https://blog.csdn.net/chenwiehuang/article/details/123447322
常见报错
centos7.6+mariadb
