Nested Dataobjects in Silverstripe 3.1? - silverstripe

Question

Is it possible to create nested Dataobjects in Silverstripe?
I tried it with an $has_many relation but the second dataobject wasn't shown in the first.
is this possible? how?

Answer 1

a hierachy of nested DataObjects was always possible in SilverStripe.
It was just the interface that was not exisiting or pretty bad in any version prior to 3.0
as of 3.0 you can nest GridFields as much as you want, not only once, you can nest it n times.
nesting dataobjects is nothing special, it is just the same as a relation from a page to a dataobject.
the relation can be has_many with a has_one on the other side, or a many_many with a belogs_many_many on the other side.
here an example with has_many:
class TournamentPage extends Page {
private static $has_many = array('Teams' => 'Team');
public function getCMSFields() {
$fields = parent::getCMSFields();
$fields->addFieldToTab('Root', Tab::create('TeamsTab', 'List of Teams'));
$fields->addFieldToTab('Root.TeamsTab', GridField::create('Teams', 'The Teams', $this->Teams(), GridFieldConfig_RecordEditor::create());
return $fields;
}
}
class TournamentPage_Controller extends Page_Controller {}
class Team extends DataObject {
private static $db = array('Title' => 'Varchar');
private static $has_one = array('TournamentPage' => 'TournamentPage'); // to make has_many of TournamentPage work
private static $has_many = array('Players' => 'Player');
public function getCMSFields() {
$fields = FieldList::create();
$fields->push(TextField::create('Title', 'Team name');
$fields->push(GridField::create('Players', 'The Players', $this->Players(), GridFieldConfig_RecordEditor::create());
return $fields;
}
}
class Player extends DataObject {
private static $db = array('Title' => 'Varchar');
private static $has_one = array('Team' => 'Team'); // to make has_many of Team work
private static $has_many = array('DopingProblems' => 'DopingProblem');
public function getCMSFields() {
$fields = FieldList::create();
$fields->push(TextField::create('Title', 'Player name');
return $fields;
}
}
and the template for that:
// file: TournamentPage.ss
<% loop $Teams %>
Team: $Title<br>
Number of Players in this Team: $Players.Count<br>
<ul>
<% loop $Players %>
<li>Player name: $Title</li>
<% end_loop %>
</ul>
<% end_loop %>