static public function addSecurity($maxQuantity)
  {
    SecurityCollection::verifyFields();
    extract($_POST);
    
    $errors=array();
    if(!is_numeric($quantity))
      $errors[] = 'Quantity should be number.';
    if($quantity<0)
      $errors[] = 'Quantity should positive.';      
    if($quantity>$maxQuantity)
      $errors[] = 'Quantity should be less then '.$maxQuantity;
    if(!trim($currency))
      $errors[] = 'Please choose isin';    
    /*elseif(!IsinCollection::getIsin($isin))
      $errors[] = 'Isin should be correct';*/
    if(!trim($account))
      $errors[] = 'Please choose account';    

    if(count($errors))
      return($errors);
    $query = "INSERT INTO `security` (`id` ,`id_client` ,`id_isin` ,`quantity` ,`id_custody` ,`created_at` )
              VALUES (NULL , '$_POST[userid]', '$_POST[isin]', '$_POST[quantity]', '$_POST[account]', NOW());";
//echo $query;
    $qres = mysql_query($query) or die('failed to executy query'.$query);
  }