/**
* Get first unused coupon
* @throws Gpf_DbEngine_NoRowException
* @return Pap_Db_Coupon
*/
public function getUnusedCoupon() {
$select = $this->createCouponsSelect();
$select->select->add(Pap_Db_Table_Coupons::ID);
$select->limit->set(0, 1);
$coupon = new Pap_Db_Coupon();
$coupon->setPrimaryKeyValue($select->getOneRow()->get(Pap_Db_Table_Coupons::ID));
$coupon->load();
return $coupon;
}
