protected function checkQueryType()
    {
        if(strtolower(substr($this->query, 0, 6)) == 'select')
            $this->queryType = 'select';
        elseif(strtolower(substr($this->query, 0, 6)) == 'insert')
            $this->queryType = 'insert';
        elseif(strtolower(substr($this->query, 0, 6)) == 'delete')
            $this->queryType = 'delete';
        elseif(strtolower(substr($this->query, 0, 6)) == 'update')
            $this->queryType = 'update';
        else
            $this->queryType = 'unknown';
    }