How do I solve an undefined index in PHP?-CodePudding

Before telling me in the comments that there are other multiple articles that might help me ant link me to them, I have read most of the questions posted on this website and others and none of their solutions worked for me. I'm building a website (school work so there are no safety concerns) and it's giving me the following error:

Notice: Undefined index: myusername in C:\xampp\htdocs\Anime_Heaven\login.php on line 28.

The context of the page is, as you might have noticed, a login form.

My code is the following:

<?PHP

$db = mysqli_connect('localhost','root','');
if (!$db)
{
   echo '<p> Erro: Falha na Ligação';
   exit;
}
mysqli_select_db($db,'Anime Heaven');
if($_SERVER["REQUEST_METHOD"] == "POST") {
   
   $myusername = $_POST['user'];

   $mypassword = $_POST['pass']; 
   
   $sql = ("SELECT id FROM login WHERE user = '$myusername' and pass = '$mypassword';");
   $result = mysqli_query($db,$sql) or die(mysqli_error($db));
   $row = mysqli_num_rows($result);
   
     
   if($row == 1) {
      $registo = mysqli_fetch_array($result);
      
      $_SESSION['myusername'] = $registo['myusername'];
      require_once("main.html");
      
  
   }else {
      $error = "Your Login Name or Password is invalid";
   }
}
?>

When I input the right username and password, it does redirect me to the correct page but it shows the error the way it's shown below:

I would be very glad if someone could help me. Thank you for reading.

CodePudding user response：

Your error message does not really match your code. Message says "index: username" but you are checking for $registo['myusername']. Anyway, in your query you do only a select for the id! Your $registo can't have a "myusername". Select all the fields you need and also check afterwards if the array has that key before assigning it to the session.

CodePudding user response：

There are two methods can be used:

use isset() to check if such index exists:

if (isset($registo['myusername']))
{
   $_SESSION['myusername'] = $registo['myusername'];
}

use @ to suppress any warning.

$_SESSION['myusername'] = @$registo['myusername'];