Hi,

I want to give our users in the database a unique alpha-numeric id. I am using the code below, will this always generate a unique id? Below is the updated version of the code:

old php:

// Generate Guid 
function NewGuid() { 
    $s = strtoupper(md5(uniqid(rand(),true))); 
    $guidText = 
        substr($s,0,8) . '-' . 
        substr($s,8,4) . '-' . 
        substr($s,12,4). '-' . 
        substr($s,16,4). '-' . 
        substr($s,20); 
    return $guidText;
}
// End Generate Guid 

$Guid = NewGuid();
echo $Guid;
echo "<br><br><br>";

New PHP:

// Generate Guid 
function NewGuid() { 
    $s = strtoupper(uniqid("something",true)); 
    $guidText = 
        substr($s,0,8) . '-' . 
        substr($s,8,4) . '-' . 
        substr($s,12,4). '-' . 
        substr($s,16,4). '-' . 
        substr($s,20); 
    return $guidText;
}
// End Generate Guid 

$Guid = NewGuid();
echo $Guid;
echo "<br><br><br>";

Will the second (new php) code guarantee 100% uniqueness.

Final code:

PHP

// Generate Guid function NewGuid() { $s = strtoupper(uniqid(rand(),true)); $guidText = substr($s,0,8) . '-' . substr($s,8,4) . '-' . substr($s,12,4). '-' . substr($s,16,4). '-' . substr($s,20); return $guidText; } // End Generate Guid

$Guid = NewGuid(); echo $Guid;

$alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ';

function base_encode($num, $alphabet) { $base_count = strlen($alphabet); $encoded = '';

while ($num >= $base_count) {

    $div = $num/$base_count;
    $mod = ($num-($base_count*intval($div)));
    $encoded = $alphabet[$mod] . $encoded;
    $num = intval($div);
}

if ($num) $encoded = $alphabet[$num] . $encoded;
    return $encoded;

}

function base_decode($num, $alphabet) { $decoded = 0; $multi = 1;

while (strlen($num) > 0) {
    $digit = $num[strlen($num)-1];
    $decoded += $multi * strpos($alphabet, $digit);
    $multi = $multi * strlen($alphabet);
    $num = substr($num, 0, -1);
}

return $decoded;

}

echo base_encode($Guid, $alphabet);

}

So for more stronger uniqueness, i am using the $Guid as the key generator. That should be ok right?