用户信息管理

<form action='#' method='post'>
    <label for='name'>姓名：</label>
    <input type='text' id='name' name='name'><br><br>
    <label for='age'>年龄：</label>
    <input type='text' id='age' name='age'><br><br>
    <input type='submit' value='添加' name='add'>
    <input type='submit' value='修改' name='update'>
    <input type='submit' value='删除' name='delete'>
    <input type='submit' value='查询' name='search'>
</form>

<?php
// 数据库连接
$servername = 'localhost';
$username = 'root';
$password = '';
$dbname = 'test';

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

// 添加记录
if (isset($_POST['add'])) {
    $name = $_POST['name'];
    $age = $_POST['age'];
    $sql = 'INSERT INTO users (name, age) VALUES (\'$name\', \'$age\')';
    $conn->query($sql);
    echo '<p>添加成功！</p>';
}

// 修改记录
if (isset($_POST['update'])) {
    $name = $_POST['name'];
    $age = $_POST['age'];
    $sql = 'UPDATE users SET age=\'$age\' WHERE name=\'$name\'';
    $conn->query($sql);
    echo '<p>修改成功！</p>';
}

// 删除记录
if (isset($_POST['delete'])) {
    $name = $_POST['name'];
    $sql = 'DELETE FROM users WHERE name=\'$name\'';
    $conn->query($sql);
    echo '<p>删除成功！</p>';
}

// 查询记录
if (isset($_POST['search'])) {
    $name = $_POST['name'];
    $sql = 'SELECT * FROM users WHERE name=\'$name\'';
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        while ($row = $result->fetch_assoc()) {
            echo '<p>姓名：' . $row['name'] . '</p>';
            echo '<p>年龄：' . $row['age'] . '</p>';
        }
    } else {
        echo '<p>没有找到相关记录。</p>';
    }
}

$conn->close();
?>