Re: Re[2]: Duplicate entry

[Harald Fuchs <hf@xxxxxxxxxx>]

In article <13144553197.20010628041442@xxxxxxxxxxxxxxx>,
Werner Stuerenburg <ws@xxxxxxxxxxxxxxx> writes:

> function getSessionID(){
>         global $sessionID;
>         if ($sessionID) return;
>         $test = 1;
>         //start, if we have no sessionID (i.e. from a Cookie)
>         $db = newDB($db);// get a PHPLIB class instance
>         while($test){
>                 mt_srand((double)microtime()*1000000);//seed
>                 $sessionID = substr(md5(uniqid(mt_rand())), 0, 4);
>                 //generate a random key, md5 and chop it
>                 $q = "SELECT * FROM sessData
>                         WHERE sid = '$sessionID'";
>                 $db->query($q);//se if we have it already
>                 $test = $db->nf();
>                 if (!$test){//no, grab it
>                         $datum = date("Y-m-d H:i:s");
>                         $q = "INSERT INTO sessData
>                                 (sid, varsVal, datum)
>                                 VALUES ('$sessionID', 'dummySession', '$datum')";
>                         $db->query($q);
>                         if ($db->Errno) getSessionID();
>                         //if error, try again, just in case
>                 }//else it is taken, get next
>         }
> }

Doing a SELECT and then an INSERT without LOCK TABLE doesn't seem very
robust to me.  Why don't you simply try to INSERT and if it fails due
to a duplicate sid generate another session ID?

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