Insert or Update in Save() method of Datamapper

[eluser]alaminx[/eluser]
hi all!
I've just start in Datamapper.
you know, the save method use to save new object or update exists object. I want to insert the position properties if it is new object

Code:

function save()
    {
//check new object or exists object
        if(empty($this->id))
        {
            $ci =& get_instance();
            $ci->firephp->log('Change position status');
            $o = new Country();
            $o->select_max('position');
            $o->get();
            if(count($o->all)!=0)
            {
                $max=$o->position+1;
                $this->position=$max;
            }
            else
            {
                $this->postion = 1;
            }
        }
       return parent::save();
    }

How do I check current object is new or exist??

[eluser]alaminx[/eluser]
I find a good way by use exist() method

Code:

function save()
    {
//check new object or exists object
        if(!this->exist())
        {
            $ci =& get_instance();
            $ci->firephp->log('Change position status');
            $o = new Country();
            $o->select_max('position');
            $o->get();
            if(count($o->all)!=0)
            {
                $max=$o->position+1;
                $this->position=$max;
            }
            else
            {
                $this->postion = 1;
            }
        }
       return parent::save();
    }

[eluser]WanWizard[/eluser]
Isn't that what rules in the datamapper model are for?

[eluser]alaminx[/eluser]
This is my model :

Code:

<?php
class Country extends DataMapper
{
    public $table="countries";
    // --------------------------------------------------------------------
    // Relationships
    // --------------------------------------------------------------------
    public $has_many=array(
            'city',
            'experience',
            'education');
    // --------------------------------------------------------------------
    // Validation
    // --------------------------------------------------------------------
    public $validation=array(
        'name'=>array(
            'label'=>'Name of country',
            'rules'=>array('required','trim','max_length'=>100))
        );
    function __construct($id=NULL)
    {
        parent::__construct($id);
    }
    function up_position()
    {  
        $max=new Country();
        $max->select_max('position');
        $max->where('position <' ,$this->position);
        $max->get();
        $o=new country();
        $o->where('position',$max->position);
        $o->get();    
        $ci =& get_instance();
        $ci->firephp->log($o->get_sql(),$o->name);
        if($o->result_count() >0 )
        {
            $tg = $this->position;
            $this->position = $o->position;
            $o->position=$tg;
            $o->save();
          
          
            $this->save();
            return true;
        }
        else
        {
            return false;
        }
    }
    function down_position()
    {
        $min=new Country();
        $min->select_min('position');
        $min->where('position >' ,$this->position);
        $min->get();
        $o=new country();
        $o->where('position',$min->position);
        $o->get();    
        $ci =& get_instance();
        $ci->firephp->log($o->get_sql(),$o->name);
        if($o->result_count() >0 )
        {
            $tg = $this->position;
            $this->position = $o->position;
            $o->position=$tg;
            $o->save();
            $this->save();
            return true;
        }
        else
        {
            return false;
        }
    }
    function save()
    {
        if(!$this->exists())
        {          
            $o = new Country();
            $o->select_max('position');
            $o->get();
            if(count($o->all)!=0)
            {
                $max=$o->position+1;
                $this->position=$max;
            }
            else
            {
                $this->postion = 1;
            }
        }
       return parent::save();
    }
}
/* End of file country.php */
/* Location: ./application/models/country.php */

[eluser]WanWizard[/eluser]
Looks ok to me.

[eluser]alaminx[/eluser]
Other problem ?
country has many city
city has one country.
when I try save country to city . nothing insert to the "country_id" field

Code:

function add()
    {
        $country_id=$this->uri->segment(4);
        //if request is GET
        $country=new country($country_id);
      
        if($_SERVER['REQUEST_METHOD']=="GET")
        {
            $city=new city();  
        }
        //if request if POST
        else
        {
            $city=new city();
            $city->name=$this->input->post('name');
            //add country to city
            $city->country=$country;
        
            if($city->save())
            {
                redirect($this->admin.'countries/list_cities/'.$country_id);    
            }
        }
         $dis['base_url']=base_url();
         $dis['country']=$country;
         $dis['menu_active']="Country";
         $dis['title']="Add New City To {$country->name}";
         $dis['object']=$city;
         $dis['view']='city/add';
         $this->viewadmin($dis);
    }

The "country_id" of the city is NULL ???

[eluser]WanWizard[/eluser]
You can't make relations that way, see the manual:

Code:

$country=new country($country_id);
if ( $country->exists() )
{
    $city = new city();
    $city->name = 'cityname';
    $city->save();
    $country->save($city);
}

[eluser]alaminx[/eluser]
I did that way , but the country_id in city is not update. Its value is NULL.

Code:

$country=new country($country_id);
if ( $country->exists() )
{
    $city = new city();
    $city->name = 'cityname';
    $city->save();
    $country->save($city);
}

[eluser]alaminx[/eluser]

Code:

CREATE TABLE IF NOT EXISTS `cities` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `position` int(11) DEFAULT NULL,
  `name` varchar(100) DEFAULT NULL,
  `country_id` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `fk_cities_countries1` (`country_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=16 ;

CREATE TABLE IF NOT EXISTS `countries` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `position` int(11) DEFAULT NULL,
  `name` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=7 ;