# PostgreSQL 安装

> CentOS 7 安装 PostgreSQL 12

---

## 安装步骤

### 1. 安装 RPM 源

```bash
yum install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
```

### 2. 安装客户端

```bash
yum install postgresql12
```

### 3. 安装服务端

```bash
yum install postgresql12-server
```

### 4. 初始化数据库

```bash
/usr/pgsql-12/bin/postgresql-12-setup initdb
```

### 5. 启动服务

```bash
systemctl enable postgresql-12
systemctl start postgresql-12
```

---

## 配置

### 数据目录

默认数据目录：`/var/lib/pgsql/12/data/`

### 连接配置

```bash
sudo -u postgres psql
```

```sql
-- 修改 postgres 用户密码
ALTER USER postgres WITH PASSWORD '你的密码';

-- 允许远程连接
-- 编辑 pg_hba.conf
host    all    all    0.0.0.0/0    md5

-- 编辑 postgresql.conf
listen_addresses = '*'
```

---

## 常用命令

```bash
# 启动/停止/重启
systemctl start postgresql-12
systemctl stop postgresql-12
systemctl restart postgresql-12

# 连接数据库
psql -U postgres -h localhost

# 创建数据库
createdb mydb

# 备份
pg_dump -U postgres mydb > backup.sql

# 恢复
psql -U postgres mydb < backup.sql
```

---

> 参考：[PostgreSQL 官方安装指南](https://www.postgresql.org/download/linux/redhat/)