public function getQuery()
    {
        $query = null;

        switch ($this->type) {
            case self::SELECT:
                $query = $this->getSelectQuery();
                break;
            case self::INSERT:
                $query = $this->getInsertQuery();
                break;
            case self::UPDATE:
                $query = $this->getUpdateQuery();
                break;
            case self::DELETE:
                $query = $this->getDeleteQuery();
                break;
        }

        return $query;
    }