public function findRelation($entity, $relationName, $orderColumn = null, $orderType = null) {
        $this->load();
        $mapper = MapperBuilder::buildFromClassName($this->mapping, get_class($entity));
        $relation = $mapper->getRelation($relationName);
        $relationMapper = MapperBuilder::buildFromName($this->mapping, $relation->getEntity());

        $selectQuery = "SELECT tmain.* FROM `" . $relationMapper->getTable() . "` tmain ";
        $joinQuery = QueryBuilder::buildJoinRelationQuery($relation, "tmain", "j1");
        $whereQuery = "WHERE j1." . $relation->getLocalColumn() . " = '" . $entity->getId() . "'";

        $orderQuery = "";
        if (!is_null($orderColumn)) {
            $orderQuery .= "ORDER BY $orderColumn ";
            if (!is_null($orderType)) {
                $orderQuery .= "$orderType";
            } else {
                $orderQuery .= "ASC";
            }
        }

        $query = $selectQuery . $joinQuery . $whereQuery . $orderQuery;
        $queryResult = $this->getDataSource()->query($query);
        if ($queryResult) {
            $collection = new Collection($relationMapper->getClass(), $queryResult, $relationMapper);
        } else {
            $collection = new Collection($relationMapper->getClass(), array(), $relationMapper);
        }

        return $collection;
    }