NYCPHP Meetup

[felix zaslavskiy]

Should not you be doing update of lastmod at the same time you update
string ? I think you may have a logical error that is why your script
does not work.

> 
> Here's the experiment. When I load a copy into each of two windows and
> submit both so they overlap in time, I expect the first to succeed and
> the second to abort. Is there something stupid I'm doing wrong here?
> (btw I am making sure to submit something in the 'string' field that's
> different from what's in the db to ensure that my timestamp updates)
> 
> <?php
> 
> require('DB.php');
> $db=DB::connect('mysql://joe_user@localhost/test');
> $db->setFetchMode(DB_FETCHMODE_ASSOC);
> 
> if($_SERVER['REQUEST_METHOD']=='POST') {
> 
>         $db->query("set transaction isolation level READ
>         UNCOMMITTED");$db->query("start transaction");
>         // compare our timestamp with db
>         $theirs = $db->getOne("select lastmod from test01 where
>         id=1"); echo "sleeping..."; flush();
>         sleep(4);
>         if ($theirs != $_POST['lastmod']) {
>                 echo "record has been modified by someone else.
> reloading...";
>                 $db->query("rollback");
>         } else {
>                 $db->query('update test01 set string ='  .
> $db->quote($_POST['string']) . ' where id=1');
>                 $db->query("commit");
>                 echo "ok, $theirs = {$_POST['lastmod']}, updating...
>                 ";
>         }
> }
> $formData = $db->getRow("select * from test01 where id = 1");
> ?>
> 
> <form action="<?=$_SERVER['PHP_SELF']?>" method="POST">
>         Id <input type="text" size="2" name="id"
> value="<?=$formData['id']?>" /><br />
>         Last Mod <input type="text" size="24" name="lastmod"
> value="<?=$formData['lastmod']?>" /><br />
>         String <input type="text" size="30" name="string"
> value="<?=htmlspecialchars($formData['string'])?>" /><br />
>         <input type="submit" />
> </form>
> 
> FWIW I've tried this with both 4.0.13-standard and 4.0.16-max-nt-log,
> both with PEAR DB 1.6.0RC6
> 
> 
> Many many thanks,
> 
> 
> ---
> David Mintz
> http://davidmintz.org/
> 
>         "Anybody else got a problem with Webistics?" -- Sopranos 24:17
> _______________________________________________
> talk mailing list
> talk at lists.nyphp.org
> http://lists.nyphp.org/mailman/listinfo/talk
>