PHP variable appears to be null while it is not

Question

I have a small php class which i have edited a little to ask my question. The class is a shown beloww

class Register
{

    public $notification = null;

    public function __construct()
   {
       create_connection();
      $this->validate_register();
    }
    public function validate_register()
    {
            //edit: missing double quote close
        $select_register = "SELECT * FROM `student_reg`";

        if($select_register_run = mysql_query($select_register))
        {
            $rows_returned = mysql_num_rows($select_register_run);
            if($rows_returned >= 1)
            {
                $this->notification = 'error';
            }else if($rows_returned == 0){
                $this->notification = 'success';
            }
        }else{
            $this->notification = 'error';
        }

        if($this->notification != null)
        {
            echo 'not null';

        }else{ echo 'null';}
    }
}
$new_register = new Register();
?>

It is clear that from the class, at any possible level, there is a value assigned to $this->notification. But for some reason, the class 'echoes' null.

The creat_connection() i built functions works perfectly but i have ommited it for the purpose of this question.

Why is this the case?

Missing quote " at the end of this line ? $select_register = "SELECT * FROM student_reg; — Lory Huz
– Lory Huz, Commented Mar 14, 2014 at 13:25
Seems like the script can't get past this line: if($select_register_run = mysql_query($select_register)) Do you have error_reporting(E_ALL); on? — Sven
– Sven, Commented Mar 14, 2014 at 13:27
That was an error while retyping the code here.. the mysql is okay — John Kariuki
– John Kariuki, Commented Mar 14, 2014 at 13:30
What's the value on $rows_returned? Maybe it's returning a non-numerical value? — Bardo
– Bardo, Commented Mar 14, 2014 at 13:31
You don't keep the mysql connection anywhere in the class context. Missing something like $this->databaseConnection = create_connection(); You really should use PDO or Mysqli — Daniel W.
– Daniel W., Commented Mar 14, 2014 at 13:32

yitwail · Accepted Answer · 2014-03-14 13:39:25Z

1

Actually, if $rows_returned is less than 1 and not equal to 0, the code will echo 'null', so I suggest you echo $rows_returned.

answered Mar 14, 2014 at 13:39

yitwail

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Vegeta · Accepted Answer · 2014-03-14 13:44:27Z

0

Try like this...

$select_register_run = mysql_query($select_register);
if($select_register_run){
//rest code

instead of

if($select_register_run = mysql_query($select_register))

answered Mar 14, 2014 at 13:44

Vegeta

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