PHP 함수와 MySQL 데이터베이스의 상호 작용

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

// 创建一个 mysqli 对象
$conn = new mysqli($servername, $username, $password, $dbName);

// 检查连接是否成功
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
}
?>

<?php
// 准备查询语句
$sql = "SELECT * FROM table_name";

// 执行查询并存储结果
$result = $conn->query($sql);

// 遍历结果集
while ($row = $result->fetch_assoc()) {
    echo $row["column_name"] . "<br>";
}
?>

<?php
// 准备插入语句
$sql = "INSERT INTO table_name (column1, column2) VALUES ('value1', 'value2')";

// 执行插入操作
if ($conn->query($sql) === TRUE) {
    echo "记录已成功插入";
} else {
    echo "插入记录失败: " . $conn->error;
}
?>

<form action="register.php" method="post">
    <label for="username">用户名：</label><input type="text" name="username"><br>
    <label for="password">密码：</label><input type="password" name="password"><br>
    <label for="email">电子邮件：</label><input type="email" name="email"><br>
    <input type="submit" value="注册">
</form>

<?php
// 连接到数据库
include 'connect_db.php';

// 准备插入语句
$sql = "INSERT INTO users (username, password, email) VALUES (?, ?, ?)";

// 绑定用户输入的值
$stmt = $conn->prepare($sql);
$stmt->bind_param("sss", $username, $password, $email);

// 设置用户输入的值
$username = $_POST['username'];
$password = password_hash($_POST['password'], PASSWORD_DEFAULT);
$email = $_POST['email'];

// 执行插入操作
$stmt->execute();

// 关闭语句对象
$stmt->close();

// 重定向到成功页面
header('Location: success.php');
?>