public function setHeader($header)
    {
        foreach ($this->results as $name) {
            $this->columns->offsetGet($name)->setHeader($header);
        }

        return $this;
    }
public function setHeader($header)
    {
        foreach ($this->results as $name) {
            $this->columns->offsetGet($name)->setHeader($header);
        }

        return $this;
    }
public function setHeader ( $ header ) { foreach ( $ this -> results as $ name ) { $ this -> columns -> offsetGet ( $ name ) -> setHeader ( $ header ) ; } return $ this ; }
Set table header for this column.

@throws Exception\InvalidArgumentException

@param string|null $header

@return Result
Set table header for this column .