CodingForums.com - update after 24 hours

I am using magento.well, i have a database where i store users points now i want to run a query like :
get time from database points where id=$id

now i have the last time points data has been updated. So, if the data updated more then 24 hours then a new query will run and update 50 points and time of the data. Can anybody help me on that how to code it. I tried but stuck and failed. Even a example will be great.

here is my code that i have tried but no results :

well have also tested results though echo : results:

Code:

$time_current = 1330240954

$utime = 1330240832

$refresh = 10

my code:

PHP Code:


		
			
    $table = $resource->getTableName('points');
    $query = 'SELECT points FROM ' . $table . ' WHERE user_id = '. (int)$cidvar .' LIMIT 1';


    $time_current = time();
    $time_updates_last = 'SELECT time FROM ' . $table . ' WHERE user_id = '. (int)$cidvar .' LIMIT 1'; 
    $utime = $readConnection->fetchOne($time_updates_last); 
    $refresh = 10; // example time set to be 10 seconds but orginal has to be 24 hours or 86400 seconds
    $data_age = $time_current - $utime;

if($data_age >= $refresh){ 
   $write = Mage::getSingleton('core/resource')->getConnection('core_write');
    $write->query("UPDATE points SET points = points + 20 AND time = '$time_current' where user_id ='. (int)$cidvar .' LIMIT 1");
}

where did i made the mistake or why its not updating ?