public function getCollection($col)
    {
        if (mb_orig_strpos($col, '.') === false) {
            $col = $this->dbname . '.' . $col;
        } else {
            $collName = explode('.', $col, 2);
        }

        if (isset($this->collections[$col])) {
            return $this->collections[$col];
        }

        return $this->collections[$col] = new Collection($col, $this);
    }