php+layui怎么进行增删改查操作

$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检测连接
if ($conn->connect_error) {
    die("连接失败: " . $conn->connect_error);
} 
echo "连接成功";

function getUsers() {
    $sql = "SELECT * FROM users";
    $result = $conn->query($sql);
    
    if ($result->num_rows > 0) {
        // 输出数据
        while($row = $result->fetch_assoc()) {
            echo "id: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
        }
    } else {
        echo "0 结果";
    }
}

function addUser($name, $email, $password) {
    $sql = "INSERT INTO users (name, email, password) VALUES ('$name', '$email', '$password')";
    
    if ($conn->query($sql) === TRUE) {
        echo "新纪录插入成功";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

<fORM class="layui-form" action="">
  <div class="layui-form-item">
    <label class="layui-form-label">用户名</label>
    <div class="layui-input-block">
      <input type="text" name="name" lay-verify="required" placeholder="请输入用户名" autocomplete="off" class="layui-input">
    </div>
  </div>
  
  <div class="layui-form-item">
    <label class="layui-form-label">电子邮件地址</label>
    <div class="layui-input-block">
      <input type="text" name="email" lay-verify="email" placeholder="请输入电子邮件地址" autocomplete="off" class="layui-input">
    </div>
  </div>

  <div class="layui-form-item">
    <label class="layui-form-label">密码</label>
    <div class="layui-input-block">
      <input type="password" name="password" lay-verify="required" placeholder="请输入密码" autocomplete="off" class="layui-input">
    </div>
  </div>

  <div class="layui-form-item">
    <div class="layui-input-block">
      <button class="layui-btn" lay-submit lay-filter="addUser">提交</button>
    </div>
  </div>
</form>

layui.use(['form'], function () {
    var form = layui.form,
        layer = layui.layer;
    
    form.on('submit(addUser)', function (data) {
        //获取用户输入数据
        var name = data.field.name,
            email = data.field.email,
            password = data.field.password;
            
        //调用addUser函数插入新用户
        addUser(name, email, password);
        
        //清空输入框
        $('form')[0].reset();
        
        return false;
    });
});