Create unique ID

[Louic]

Hello

 

This is my first post here at phpfreaks. Hope I'll make it right. Now to my problem.

 

I want to create a unique ID (based on diffrent letters and numbers) and save it down to my MySQL-databas (column hashid). The problem is that I don't now how to make the code loop. I'll post my code with explanation.

 

            function slumpa() {
                $s = chr(mt_rand(97, 122)) . chr(mt_rand(65, 90));
                for ($i=0; $i<20;$i++) $s.= mt_rand(0, 9);
            return $s;
            }
   
            $regid = slumpa()
           
                $sql = "SELECT COUNT(hashid) FROM medlemmar WHERE hashid='{$regid}'";
                $result = mysql_query($sql);
                  if (mysql_result($result, 0) > 0) {
                    [b]// Find a new  unique ID and check if it is in the databas, if it is, make this until finding a unique one.[/b]
                  }

How to fix this?

[p2grace]

Why not just md5 a timestamp?

[GingerRobot]

You want to set a variable to false and loop until it is true - only change it's value if you find a unique id:

 

<?php
function slumpa() {
    $s = chr(mt_rand(97, 122)) . chr(mt_rand(65, 90));
    for ($i=0; $i<20;$i++) 
        $s.= mt_rand(0, 9);
return $s;
}
$unique = FALSE;
while($unique === FALSE){
    $s= slumpa();
    $result = mysql_query("SELECT COUNT(hashid) FROM medlemmar WHERE hashid='$s'");
    if(mysql_result($result,0) == 0){
        $unique = TRUE;
    }
}
//insert $s into the database
?>

 

If you're just wanting to uniquely identify a user, it'd be much easier to just use an auto-increment field, however.