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php实现mysqli

2026-01-29 12:20:26PHP

php实现mysqli

使用PHP实现MySQLi连接数据库

MySQLi（MySQL improved）是PHP中用于与MySQL数据库交互的扩展，支持面向对象和面向过程两种编程风格。

面向对象方式连接MySQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 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";
?>

面向过程方式连接MySQL

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 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";
?>

执行查询操作

$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
    }
} else {
    echo "0 结果";
}

预处理语句防止SQL注入

$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (?, ?)");
$stmt->bind_param("ss", $name, $email);

$name = "John Doe";
$email = "john@example.com";
$stmt->execute();

echo "新记录插入成功";
$stmt->close();

关闭数据库连接

$conn->close();

错误处理最佳实践

try {
    $conn = new mysqli($servername, $username, $password, $dbname);

    if ($conn->connect_errno) {
        throw new Exception("连接错误: " . $conn->connect_error);
    }

    // 执行数据库操作

} catch (Exception $e) {
    echo "数据库错误: " . $e->getMessage();
} finally {
    if (isset($conn)) {
        $conn->close();
    }
}

事务处理示例

$conn->autocommit(FALSE);

try {
    $conn->query("UPDATE accounts SET balance = balance - 100 WHERE user_id = 1");
    $conn->query("UPDATE accounts SET balance = balance + 100 WHERE user_id = 2");

    $conn->commit();
    echo "事务成功完成";
} catch (Exception $e) {
    $conn->rollback();
    echo "事务失败: " . $e->getMessage();
}

MySQLi提供了比旧版MySQL扩展更安全、更高效的功能，特别是预处理语句和事务支持。建议在新项目中使用MySQLi或PDO扩展，避免使用已废弃的mysql_*函数。