PHP 函数参数绑定的目的和作用？

<?php // 创建 MySQLi 链接$mysqli = new mysqli("localhost", "root", "password", "my_database");// 准备 SQL 查询$stmt = $mysqli->prepare("SELECT id, name FROM users WHERE email = ?");// 绑定参数$stmt-&gt;bind_param("s", $email);// 设置参数值$email = "example@domain.com";// 执行查询$stmt-&gt;execute();// 获取结果$result = $stmt-&gt;get_result();// 遍历查询结果while ($row = $result-&gt;fetch_assoc()) {    echo "ID: " . $row["id"] . ", Name: " . $row["name"] . "<br>";}// 关闭数据库连接$stmt-&gt;close();$mysqli-&gt;close();?&gt;