class AreaHolder extends Page {
static $has_many = array(
'Areas' => 'Area'
);

function getCMSFields() {
$fields = parent::getCMSFields();

$grid_Config = GridFieldConfig_RecordEditor::create();
$grid_Config->getComponentByType('GridFieldDataColumns')
->setDisplayFields(array(
'Title' => 'Name',
'RouteCount' => 'Anzahl Routen'
));

$fields->addFieldToTab('Root.Klettergebiete',
new GridField('Klettergebiete', 'Klettergebiete', $this->Areas(), $grid_Config));
return $fields;
}
}

class AreaHolder_Controller extends Page_Controller {
}

class Area extends DataObject {
static $db = array(
'Title' => 'Varchar(255)'
);

static $has_one = array(
'Page' => 'AreaHolder'
);

static $has_many = array(
'Sectors' => 'Sector',
'SinglePitches' => 'SinglePitch',
'MultiPitches' => 'MultiPitch'
);

function getRouteCount() {
return $this->SinglePitches()->Count() + $this->MultiPitches()->Count();
}

function getCMSFields() {

$fields = new FieldList(
new TabSet('Root',
new Tab('Main', 'Hauptteil'),
new Tab('SinglePitch', 'Einseillängen'),
new Tab('MultiPitch', 'Mehrseillängen')
));

$fields->addFieldToTab('Root.Main', new TextField('Title', 'Name', $this->Title));
$fields->addFieldToTab('Root.Main', new GridField('Sectors','Sektoren', $this->Sectors(), GridFieldConfig_RecordEditor::create();));
$fields->addFieldToTab('Root.SinglePitch', new GridField('SinglePitches', 'Einseillängenrouten', $this->SinglePitches(), GridFieldConfig_RecordEditor::create();));
$fields->addFieldToTab('Root.MultiPitch', new GridField('MultiPitches', 'Mehrseillängenrouten', $this->MultiPitches(), GridFieldConfig_RecordEditor::create();));
return $fields;
}
}