public function addField($name, $value)
    {
        if (!array_key_exists($name, $this->row)) {
            $this->row[$name] = $value;
        } elseif (is_array($this->row[$name])) {
            $this->row[$name][] = $value;
        } else {
            $this->row[$name] = array($this->row[$name], $value);
        }
        $this->informChanges();
    }