> For the complete documentation index, see [llms.txt](https://book.bsdcn.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://book.bsdcn.org/di-33-zhang-shu-ju-ku-guan-li/di-33.4-jie-mysql.md).

# 33.4 MySQL

MySQL 是由 Oracle 公司主导开发的开源关系型数据库管理系统（Relational Database Management System，RDBMS）。

MySQL 9.7 是最新长期支持（LTS）版本，MySQL 8.4 是上一个长期支持（LTS）版本。

## 安装 MySQL 8.4 LTS

使用 pkg 安装：

```sh
# pkg install mysql84-server
```

或使用 Ports 编译安装：

```sh
# cd /usr/ports/databases/mysql84-server/
# make install clean
```

查看安装后的说明：

```sh
# pkg info -D mysql84-server
```

## 安装 MySQL 9.7 LTS

使用 pkg 安装：

```sh
# pkg install mysql97-server
```

或使用 Ports 编译安装：

```sh
# cd /usr/ports/databases/mysql97-server/
# make install clean
```

查看安装后的说明：

```sh
# pkg info -D mysql97-server
```

## 启动服务

安装完成后，需启动 MySQL 服务才能使用。

设置 MySQL 服务开机自启：

```sh
# service mysql-server enable
```

立即启动 MySQL 服务：

```sh
# service mysql-server start
```

## 登录

服务启动后，可以使用命令行客户端（作为依赖将自动安装）登录 MySQL。根据安装说明，MySQL 8.4、9.7 的默认密码为空，登录时直接按回车即可。

使用 root 用户登录 MySQL 服务器，提示输入密码：

```sql
# mysql -uroot -p
Enter password: # 此处直接按回车键
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.4.9 Source distribution

Copyright (c) 2000, 2026, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql>
```

## 修改密码

为了数据库安全，首次登录后建议立即修改 root 用户密码。以下命令将数据库的 root 用户密码设置为 `SecurePass123!`，修改后立即生效，最后退出 MySQL。

```sql
mysql> alter user 'root'@'localhost' identified by 'SecurePass123!'; -- 修改 root 用户的密码为 SecurePass123!，ALTER USER 直接修改授权表并立即生效
Query OK, 0 rows affected (0.01 sec)

mysql> quit; -- 退出 MySQL 命令行客户端
Bye
```

> **技巧**
>
> 上述示例中的 `SecurePass123!` 为占位符，需要替换为实际的值。

重新登录：

```sql
# mysql -uroot -p  # 使用 root 用户登录 MySQL，并按提示输入密码
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.4.9 Source distribution

Copyright (c) 2000, 2026, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

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

mysql> show databases; -- 显示当前 MySQL 实例中的所有数据库
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.00 sec)

mysql> quit; -- 退出 MySQL 命令行客户端
Bye
```

## MySQL 配置文件

MySQL 的配置文件结构如下。

```sh
/
└── usr/
    └── local/
       └── etc/
           └── mysql/
                ├── my.cnf        # MySQL 配置文件
                └── my.cnf.sample # MySQL 配置文件示例

```

如需进一步配置 MySQL，可以修改其配置文件。配置文件可以调整数据库的各种参数，如内存使用、连接数等。

MySQL 默认的配置文件模板位于 **/usr/local/etc/mysql/my.cnf.sample**，实际的默认配置文件位于 **/usr/local/etc/mysql/my.cnf**（默认内容为空）。

复制 MySQL 示例配置文件为正式配置文件：

```sh
# cp /usr/local/etc/mysql/my.cnf.sample /usr/local/etc/mysql/my.cnf
```

随后根据需要修改 **/usr/local/etc/mysql/my.cnf** 文件即可。

如需使用自定义的配置文件路径，可在 **/etc/rc.conf** 文件中写入：

```ini
mysql_optfile="/abc/xyz.cnf"
```


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