Question

Please explain me why that code:

    class kategoria
    {
        public $IdKat;
        public $NazwaKat;
        public $OpisKat;
    }

    class dbClass  
    {  
        private $link;

        private $user = USER;
        private $pass = PASS;
        private $database = DATABASE;



        function __construct()  
        {  
            try
            {
                $this->link = new mysqli('localhost', $this->user, $this->pass, $this->database);  
                $this->link->set_charset('utf8');
            ;
            }
            catch(Exception $exc)
            {
                echo $e;
            }
        }  


        function get_cats()  
        {  

            $query = "SELECT IdKat, NazwaKat, OpisKat  FROM `kategorie`"; 

            try
            {
                $stmt = $this->link->prepare($query);

                /* bind parameters for markers */
                //$stmt->bind_param("i", $IdKat);

                $stmt->execute();
                $kat = new kategoria();

                $stmt->bind_result(
                        $kat->IdKat, 
                        $kat->NazwaKat, 
                        $kat->OpisKat
                        );


                $output = array();
                $output2 = array();

                while ($stmt->fetch()) {

                    array_push($output, $kat->IdKat);
                    array_push($output2, $kat);
                    // array_push($output2, clone $kat); // i tried cloning like this
                    // $output2 += array(clone($kat)); // tried adding
                }

                $stmt->close();
            }
            catch (Exception $e)
            {
                echo $e;
            }

            echo '<pre>';
            print_r($output);
            echo '</pre>';
            echo '--------------------------<br/>';

            echo '<pre>';
            print_r($output2);
            echo '</pre>';
        }  

    }  

Gives me data like this:

Array (
    [0] => 2
    [1] => 3
    [2] => 4 )

--------------------------

Array (
 [0] => kategoria Object
     (
         [IdKat] => 4
         [NazwaKat] => Hi-Fi
         [OpisKat] => Music equipment
     )

 [1] => kategoria Object
     (
         [IdKat] => 4
         [NazwaKat] => Hi-Fi
         [OpisKat] => Music equipment
     )

 [2] => kategoria Object
     (
         [IdKat] => 4
         [NazwaKat] => Hi-Fi
         [OpisKat] => Music equipment
     )

 )

This is my second question about it. I tried adding arrays, cloning object $kat and it didnt worked. Finally i made another array and im using both for debugging.

It looks weird. I dont understand why cloned object in array is overwriten after next row fetching. It supposed be a copy of his clone, right?

Answer 1

I found answer in PHP help. I had to create “deep copy” like this:

$clone = unserialize(serialize($object)); 

Because (i believe) help says: “Any properties that are references to other variables, will remain references.”