如何使用 PHP 函数来操作数据库

<?php $servername = "localhost";$username = "root";$password = "password";$dbname = "mydb";// 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-&gt;connect_error);}?&gt;

<?php // 预备查询$stmt = $conn->prepare("SELECT * FROM customers WHERE name = ?");// 绑定参数$stmt-&gt;bind_param("s", $name);// 设置参数$name = "John Doe";// 执行查询$stmt-&gt;execute();// 绑定结果$stmt-&gt;bind_result($id, $name, $email);// 循环结果while ($stmt-&gt;fetch()) {    echo "ID: $id, 姓名: $name, 邮箱: $email<br>";}// 关闭语句$stmt-&gt;close();?&gt;

<?php // 预备查询$stmt = $conn->prepare("INSERT INTO customers (name, email) VALUES (?, ?)");// 绑定参数$stmt-&gt;bind_param("ss", $name, $email);// 设置参数$name = "Jane Doe";$email = "jane.doe@example.com";// 执行查询$stmt-&gt;execute();// 获取自增 ID（如果有）$id = $conn-&gt;insert_id;// 关闭语句$stmt-&gt;close();echo "新记录已插入，ID 为：$id";?&gt;

<?php // 预备查询$stmt = $conn->prepare("UPDATE customers SET name = ? WHERE id = ?");// 绑定参数$stmt-&gt;bind_param("si", $name, $id);// 设置参数$name = "John Smith";$id = 1;// 执行查询$stmt-&gt;execute();// 关闭语句$stmt-&gt;close();echo "记录已更新";?&gt;

<?php // 预备查询$stmt = $conn->prepare("DELETE FROM customers WHERE id = ?");// 绑定参数$stmt-&gt;bind_param("i", $id);// 设置参数$id = 1;// 执行查询$stmt-&gt;execute();// 关闭语句$stmt-&gt;close();echo "记录已删除";?&gt;

<?php // 关闭连接$conn->close();?&gt;

<?php // 连接数据库...// 查询博客文章$stmt = $conn->prepare("SELECT * FROM blog_posts ORDER BY created_at DESC");$stmt-&gt;execute();$stmt-&gt;bind_result($id, $title, $content, $created_at);// 循环结果，显示博客文章while ($stmt-&gt;fetch()) {    echo "<h1>$title</h1>";    echo "<p>$content</p>";    echo "<p>Created: $created_at</p>";    echo "<hr>";}// 关闭语句$stmt-&gt;close();?&gt;