php使用insert语句动态添加用户

<html>
<head>
   <title>Adding User</title>
</head>
<body>
  <h2>Adding users to mysql database.</h2>
  <form action="insertformhandler.php" method="post">
    Select gender:
         <select name="gender">
           <option value="male">man</option>
           <option value="female">woman</option>
         </select><br />
    Fill user name:
     <input name="username" type="text" size="20"/> <br />
        Fill user age:
     <input name="age" type="text" size="3"/> <br />
        Fill user info:
     <input name="info" type="text" size="60"/> <br />
         <input name="submit" type="submit" value="Add"/>
  </form>
</body>
</html>

  

<html>
<head>
   <title>User adding</title>
</head>
<body>
   <h2>adding new user.</h2>
<?php
    $username = $_POST['username'];
        $gender = $_POST['gender'];
        $age = $_POST['age'];
        $info = $_POST['info'];
        if(!$username and !$gender and !$age and !$info){
            echo "Error: There is no data passed.";
                exit;
        }
    if(!$username or !$gender or !$age or !$info){
            echo "Error: Some data did not be passed.";
                exit;
        }
        if(!get_magic_quotes_gpc()){
            $username = addslashes($username);
                $gender = addslashes($gender);
                $age = addslashes($age);
                $info = addslashes($info);
        }
                @ $db = mysqli_connect('localhost','root','12345678');
                mysqli_select_db($db,'testphp');
                if(mysqli_connect_errno()){
                 echo "Error: Could not connect to mysql database.";
                 exit;
                }
                $q = "INSERT INTO user( id,name, age, gender, info) VALUES (2,'$username',$age,'$gender', '$info')";
                if( !mysqli_query($db,$q)){
                   echo "no new user has been added to database.";
                }else{
                   echo "New user has been added to database.";
                };
                mysqli_close($db);
?>
</body>
</html>