code: 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();
      }
docs: Add a string field to row
  @param string $name
  @param string $value