小弟用XAMPP試著上傳資料到mysql資料庫。
我上傳時沒有跳error出來，但mysql沒有我上傳的資料
請問這是什麼問題??(感恩)

code

html

<form name="file" method="POST" action="PHP/make_case.php">
	<fieldset id="case1">
		<div class="fielsettitle"><legend>個資</legend></div>
		<p>
			<label>email<input  class="useremail" type="email" name="email" required></label>
			<label>姓名<input class="username" type="text" name="username"  required></label>
		</p>
	</fieldset>
	<fieldset id="case2">
		<div class="fielsettitle"><legend>case</legend></div>
		<p>
			<label>Case Title<input class="casetitle" type="text" name="casetitle" required></label>
			<label>Case 說明<input class="casemain" type="text" name="casemain" required></label>
		</p>
	</fieldset>
	<fieldset id="case3">
		<div class="fielsettitle"><legend>人</legend></div>
		<p>
			<label>需要哪種人<input class="people" type="text" name="people" required></label>
		</p>
	</fieldset>
	<center><input type='submit' value='提交'></center>
</form>			

PHP

(make_case.php)

<?php
    require_once("dbtools.inc.php");
    $email=$_POST["email"];
    $username=$_POST["username"];
    $case_title=$_POST["casetitle"];
    $case_discription=$_POST["casemain"];
    $peoples=$_POST["people"];
    
    $link=create_connection();
    $sql="INSERT INTO people_data(name,email,casetitle,casemain,people)VALUES($username,$email,$case_title,$case_discription,$peoples)";
    $result=execute_sql($link,"makecase",$sql);
    // mysql_close($link);
    // header("Location:/index.html")
?>

(dbtools.inc.php)

<?php
  function create_connection()
  {
    $link = mysqli_connect("localhost", "root", "123456")
      or die("無法建立資料連接: " . mysqli_connect_error());
	  
    mysqli_query($link, "SET NAMES utf8");
			   	
    return $link;
  }
	
  function execute_sql($link, $database, $sql)
  {
    mysqli_select_db($link, $database)
      or die("開啟資料庫失敗: " . mysqli_error($link));
						 
    $result = mysqli_query($link, $sql);
		
    return $result;
  }
?>

資料庫