CentOS7 安装 mariadb

MariaDB 数据库管理系统是 MySQL 的一个分支，主要由开源社区在维护，采用 GPL 授权许可。开发这个分支的原因之一是：甲骨文公司收购了 MySQL 后，有将 MySQL 闭源的潜在风险，因此社区采用分支的方式来避开这个风险。MariaDB完全兼容mysql，使用方法也是一样的

有的centos7已经默认安装了Mariadb，可以查看自己的有没有安装，没有安装的再进行安装，已经安装了可以不用安装也可以卸载了重装。卸载命令
yum remove mariadb-server

[root@mini ~]# cat /etc/redhat-release
CentOS Linux release 7.5.1804 (Core)

1、安装MariaDB

# 通过yum安装就行了。简单快捷，安装mariadb-server，默认依赖安装mariadb，一个是服务端、一个是客户端。
yum install mariadb-server -y

2、配置MariaDB

1）安装完成后首先要把MariaDB服务开启，并设置为开机启动

systemctl enable mariadb --now
# 启动完之后，可以直接配置 password ，详细请执行：grep pass /var/log/messages
/usr/bin/mysqladmin -u root password 'new-password'

2）首次安装需要进行数据库的配置，命令都和mysql的一样

mysql_secure_installation

3）配置时出现的各个选项

Enter current password for root (enter for none):  # 输入数据库超级管理员root的密码(注意不是系统root的密码)，第一次进入还没有设置密码则直接回车

Set root password? [Y/n]  # 设置密码，y

New password:  # 新密码
Re-enter new password:  # 再次输入密码

Remove anonymous users? [Y/n]  # 移除匿名用户， y

Disallow root login remotely? [Y/n]  # 拒绝root远程登录，n，不管y/n，都会拒绝root远程登录

Remove test database and access to it? [Y/n]  # 删除test数据库，y：删除。n：不删除，数据库中会有一个test数据库，一般不需要

Reload privilege tables now? [Y/n]  # 重新加载权限表，y。或者重启服务也许

4）测试是否能够登录成功，出现 MariaDB [(none)]> 就表示已经能够正常登录使用MariaDB数据库了

# mysql -u root -p
Enter password:
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 8
Server version: 5.5.60-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)]>

3、设置MariaDB字符集为utf-8

1）/etc/my.cnf 文件
在 [mysqld] 标签下添加

init_connect='SET collation_connection = utf8_unicode_ci'
init_connect='SET NAMES utf8'
character-set-server=utf8
collation-server=utf8_unicode_ci
skip-character-set-client-handshak

2）/etc/my.cnf.d/client.cnf 文件
在 [client] 标签下添加

default-character-set=utf8

3）/etc/my.cnf.d/mysql-clients.cnf 文件
在 [mysql] 标签下添加

default-character-set=utf8

4）重启服务

systemctl restart mariadb

5）进入mariadb查看字符集

MariaDB [(none)]> show variables like "%character%";show variables like "%collation%";
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | latin1                     |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | latin1                     |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.01 sec)

+----------------------+-------------------+
| Variable_name        | Value             |
+----------------------+-------------------+
| collation_connection | utf8_general_ci   |
| collation_database   | latin1_swedish_ci |
| collation_server     | latin1_swedish_ci |
+----------------------+-------------------+
3 rows in set (0.00 sec)

MariaDB [(none)]>

未配置字符集前

MariaDB [(none)]> show variables like "%character%";show variables like "%collation%";
+--------------------------+----------------------------+
| Variable_name            | Value                      |
+--------------------------+----------------------------+
| character_set_client     | utf8                       |
| character_set_connection | utf8                       |
| character_set_database   | utf8                       |
| character_set_filesystem | binary                     |
| character_set_results    | utf8                       |
| character_set_server     | utf8                       |
| character_set_system     | utf8                       |
| character_sets_dir       | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.00 sec)

+----------------------+-----------------+
| Variable_name        | Value           |
+----------------------+-----------------+
| collation_connection | utf8_unicode_ci |
| collation_database   | utf8_unicode_ci |
| collation_server     | utf8_unicode_ci |
+----------------------+-----------------+
3 rows in set (0.00 sec)

MariaDB [(none)]>

配置字符集后

4、远程链接mariadb数据库

mariadb默认是拒绝 root 远程登录的。这里用的是 navicat 软件连接数据库
1）关闭防火墙
① 关闭防火墙 systemctl stop firewalld

systemctl stop firewalld

② 在不关闭防火墙的情况下，允许某端口的外来链接。步骤如下，开启3306端口，重启防火墙

[root@mini ~]# firewall-cmd --query-port=3306/tcp  # 查看3306端口是否开启
no
[root@mini ~]# firewall-cmd --zone=public --add-port=3306/tcp --permanent  # 开启3306端口
success
[root@mini ~]# firewall-cmd --reload  # 重启防火墙
success
[root@mini ~]# firewall-cmd --query-port=3306/tcp  # 查看3306端口是否开启
yes

2）先查看mysql数据库中的user表

[root@mini ~]# mysql -u root -p  # 先通过本地链接进入数据库

MariaDB [(none)]> use mysql;

MariaDB [mysql]> select host, user from user;
+-----------+------+
| host      | user |
+-----------+------+
| 127.0.0.1 | root |
| ::1       | root |
| mini      | root |
+-----------+------+
3 rows in set (0.00 sec)

3）将与主机名相等的字段改为 "%" ，我的主机名为mini，

MariaDB [mysql]> update user set host='%' where host='mini';
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [mysql]> select host, user from user;
+-----------+------+
| host      | user |
+-----------+------+
| %         | root |
| 127.0.0.1 | root |
| localhost | root |
+-----------+------+
3 rows in set (0.00 sec)

4）刷新权限表，或重启mariadb服务，一下二选一即可

MariaDB [mysql]> flush privileges;
Query OK, 0 rows affected (0.00 sec)

systemctl restart mariadb

注意：刷新权限表是在数据库中，重启服务是在外部命令行中

6）重新远程链接mariadb