为什么这个php脚本是错误的，我'；我收到很多错误信息

为了便于学习，我编写了这个PHP脚本，以便将数据保存到mysql数据库中

我的最后一个任务是通过我正在开发的Xcode应用程序使用Alamofire发出post请求

但作为试用，我正在使用“邮递员应用程序”测试post请求

下面是我的php脚本：

<?php

$host = "127.0.0.1";
$user = "root";
$password = "";
$database = "login_db";

$staff = $_POST['staff_ID'];
$password = $_POST['password'];
$email = $_POST['email'];
$cpt = $_POST['isCPT'];
$name = $_POST['Name'];



$connessione = new mysqli($host,$user,$password,$database);

if ($connessione === false) {

    die("errore connessione db " .$connessione->connection_error);

}

$query = "INSERT INTO users (staff_ID , password, email,  isCPT,  Name ) VALUES(?, ?, ?, ?, ?)";
 
$stmt = $connessione->prepare($query);  //Prepare
$stmt->bind_param("sssss", $staff,$password,$email,$cpt,$name);  //Bind
$stmt->execute();//Execute
if($stmt->affected_rows === 0) exit('Nothing was inserted.');  //Check to see if it worked
$stmt->close();
$connessione -> close();

?>

错误：

<br />
<b>Warning</b>:  Undefined array key "staff_ID" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>8</b><br />
<br />
<b>Warning</b>:  Undefined array key "password" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>9</b><br />
<br />
<b>Warning</b>:  Undefined array key "email" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>10</b><br />
<br />
<b>Warning</b>:  Undefined array key "isCPT" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>11</b><br />
<br />
<b>Warning</b>:  Undefined array key "Name" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>12</b><br />
<br />
<b>Warning</b>:  Undefined variable $mysqli in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>35</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function prepare() on null in E:\XAMPP\htdocs\test\nxSignUp.php:35
Stack trace:
#0 {main}
  thrown in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>35</b><br />

警告：第8行E:\XAMPP\htdocs\test\nxSignUp.php中未定义的数组键“staff\u ID”



警告：第9行E:\XAMPP\htdocs\test\nxSignUp.php中未定义的数组键“password”



警告：第10行E:\XAMPP\htdocs\test\nxSignUp.php中未定义的数组键“email”



警告：第11行E:\XAMPP\htdocs\test\nxSignUp.php中未定义的数组键“isCPT”



警告：第12行E:\XAMPP\htdocs\test\nxSignUp.php中未定义的数组键“Name”



警告：第35行E:\XAMPP\htdocs\test\nxSignUp.php中未定义变量$mysqli



致命错误：未捕获错误：在E:\XAMPP\htdocs\test\nxSignUp.php:35中调用null上的成员函数prepare（）
堆栈跟踪：
#0{main}
在第35行的E:\XAMPP\htdocs\test\nxSignUp.php中抛出

您是通过URL发送这些参数，而不是通过请求正文发送。您没有$mysqli您有$connessionEthaks，我更正了$connessione错误，但仍有许多错误显示：警告：未定义的数组键“staff\u ID”在第8行的E:\XAMPP\htdocs\test\nxSignUp.php中，
看起来post请求没有传递任何数据。如果您刚刚开始学习php，那么您应该学习PDO而不是mysqli。PDO更简单，更适合初学者。从这里开始&

<br />
<b>Warning</b>:  Undefined array key "staff_ID" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>8</b><br />
<br />
<b>Warning</b>:  Undefined array key "password" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>9</b><br />
<br />
<b>Warning</b>:  Undefined array key "email" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>10</b><br />
<br />
<b>Warning</b>:  Undefined array key "isCPT" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>11</b><br />
<br />
<b>Warning</b>:  Undefined array key "Name" in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>12</b><br />
<br />
<b>Warning</b>:  Undefined variable $mysqli in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>35</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to a member function prepare() on null in E:\XAMPP\htdocs\test\nxSignUp.php:35
Stack trace:
#0 {main}
  thrown in <b>E:\XAMPP\htdocs\test\nxSignUp.php</b> on line <b>35</b><br />