Question

I am missing something obvious. Here’s a trivial piece of PHP, littered with debug echos:

function echo_rows(&$res) {
    $rows= array();
    while ($row= $res->fetch()) {
           echo $row['ccorID'] . "\r\n";
        $rows[]= $row;
           echo $rows[0]['ccorID'] . "\r\n";
    }

    echo "---.---\r\n";
    echo count($rows) . "\r\n";
    foreach($rows as $row) {
        echo $row['ccorID'] . "\r\n";
    }
    echo json_encode($rows);
}

Here’s what I see in the response:

0
0
3
3
13
13
182
182
---.---
4
182
182
182
182

It seems perfectly clear to me that :-

• I have 4 rows of data
• $rows[]= $row; does NOT perform a value copy, despite what it says here http://uk.php.net/manual/en/language.types.array.php

Anyone got any idea what I need to do to get a copy of $row (which is an associative array)?

Thanks.

EDIT: Since many of you are so insistent to know what $res is, here is the class. I genuinely believe that this is more likely to confuse than enlighten (hence the omission from my OP).

class mysqlie_results {
    private $stmt;
    private $paramArray= array(); 
    private $assocArray= array(); 

    public function __construct(&$stmt) {
        $this->stmt= $stmt;
        $meta= $stmt->result_metadata(); 

        while ($colData= $meta->fetch_field()) {
            $this->paramArray[]= &$this->assocArray[$colData->name]; 
        }

        call_user_func_array(array($stmt,'bind_result'),$this->paramArray); 
        $meta->close(); 
    } 

    public function __destruct() {
        $this->stmt->free_result();
    } 

    public function fetch() { 
        return $this->stmt->fetch()? $this->assocArray : false;
    } 
} 

Answer 1

Let’s take a closer look at

    while ($colData= $meta->fetch_field()) {
        $this->paramArray[]= &$this->assocArray[$colData->name]; 
    }

    call_user_func_array(array($stmt,'bind_result'),$this->paramArray);

There you have your reference(s) and that’s causing the trouble. If you copy an array that contains a reference the result is still an array containing a reference.

Try

while ($row= $res->fetch()) {
  var_dump($row);

and you will see that $row also contains references. All those corresponding elements in paramArray, assocArray and $row actually reference the same value. And thus when you invoke return $this->stmt->fetch() it doesn’t only affect paramArray but all those references, all the way down to $rows since $rows[]= $row; still only copies the array but does not “de-reference” the elements.