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PHP怎样连接MySQL数据库？

news 2025/5/10 11:49:27

方法一：使用 mysqli 扩展

mysqli 是 MySQL 的改进版扩展，提供了面向对象和过程化的接口。

面向对象风格

<?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";// 执行查询示例
$sql = "SELECT id, name FROM your_table";
$result = $conn->query($sql);if ($result->num_rows > 0) {// 输出数据while($row = $result->fetch_assoc()) {echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";}
} else {echo "0 结果";
}// 关闭连接
$conn->close();?>

过程化风格

<?php$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);// 检查连接
if (!$conn) {die("连接失败: " . mysqli_connect_error());
}echo "连接成功";// 执行查询示例
$sql = "SELECT id, name FROM your_table";
$result = mysqli_query($conn, $sql);if (mysqli_num_rows($result) > 0) {// 输出数据while($row = mysqli_fetch_assoc($result)) {echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";}
} else {echo "0 结果";
}// 关闭连接
mysqli_close($conn);?>

方法二：使用 PDO 扩展

PDO 提供了一个统一的接口来访问多种数据库，支持参数化查询，能有效防止SQL注入。

<?php$servername = "localhost";
$username = "your_username";
$password = "your_password";
$dbname = "your_database";try {// 创建连接$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";// 执行查询示例$sql = "SELECT id, name FROM your_table";$stmt = $conn->prepare($sql);$stmt->execute();// 设置结果为关联数组$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);foreach ($stmt->fetchAll() as $row) {echo "id: " . $row["id"]. " - Name: " . $row["name"]. "<br>";}
} catch(PDOException $e) {echo "连接失败: " . $e->getMessage();
}// 连接会在脚本结束时自动关闭，但你可以显式关闭
$conn = null;?>