ubuntu里php如何连接数据库

在Ubuntu系统中，PHP可以通过多种方式连接到数据库。以下是一些常见的数据库及其连接方法：

1. MySQL/MariaDB

使用mysqli扩展

<?php $servername = "localhost"; $username = "your_username"; $password = "your_password"; $dbname = "your_database"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检查连接 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } echo "连接成功"; // 执行SQL查询 $sql = "SELECT id, name FROM users"; $result = $conn->query($sql); if ($result->num_rows > 0) { // 输出每行数据 while($row = $result->fetch_assoc()) { echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>"; } } else { echo "0 结果"; } $conn->close(); ?> 

使用PDO扩展

<?php $servername = "localhost"; $username = "your_username"; $password = "your_password"; $dbname = "your_database"; try { $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password); // 设置 PDO 错误模式为异常 $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); echo "连接成功"; $stmt = $conn->query("SELECT id, name FROM users"); while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) { echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>"; } } catch(PDOException $e) { echo "连接失败: " . $e->getMessage(); } $conn = null; ?> 

2. PostgreSQL

使用mysqli扩展

<?php $servername = "localhost"; $username = "your_username"; $password = "your_password"; $dbname = "your_database"; // 创建连接 $conn = new mysqli($servername, $username, $password, $dbname); // 检查连接 if ($conn->connect_error) { die("连接失败: " . $conn->connect_error); } echo "连接成功"; // 执行SQL查询 $sql = "SELECT id, name FROM users"; $result = $conn->query($sql); if ($result->num_rows > 0) { // 输出每行数据 while($row = $result->fetch_assoc()) { echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>"; } } else { echo "0 结果"; } $conn->close(); ?> 

使用PDO扩展

<?php $servername = "localhost"; $username = "your_username"; $password = "your_password"; $dbname = "your_database"; try { $conn = new PDO("pgsql:host=$servername;dbname=$dbname", $username, $password); // 设置 PDO 错误模式为异常 $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); echo "连接成功"; $stmt = $conn->query("SELECT id, name FROM users"); while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) { echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>"; } } catch(PDOException $e) { echo "连接失败: " . $e->getMessage(); } $conn = null; ?> 

3. SQLite

使用SQLite3扩展

<?php $dbname = "your_database.db"; // 创建连接 $conn = new SQLite3($dbname); // 检查连接 if (!$conn) { die("连接失败"); } echo "连接成功"; // 执行SQL查询 $result = $conn->query("SELECT id, name FROM users"); if ($result) { while ($row = $result->fetchArray(SQLITE3_ASSOC)) { echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>"; } } else { echo "查询失败"; } $conn->close(); ?> 

安装扩展

如果你还没有安装相应的PHP扩展，可以使用以下命令进行安装：

安装mysqli扩展

sudo apt-get install php-mysql 

安装PDO扩展

sudo apt-get install php-pdo 

安装PDO MySQL扩展

sudo apt-get install php-mysqlnd 

安装PDO PostgreSQL扩展

sudo apt-get install php-pgsql 

安装SQLite3扩展

sudo apt-get install php-sqlite3 

安装完成后，重启你的Web服务器（例如Apache或Nginx）以使更改生效：

sudo systemctl restart apache2 # 对于Apache sudo systemctl restart nginx # 对于Nginx 

通过以上步骤，你应该能够在Ubuntu系统中使用PHP连接到不同的数据库。