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Data Model Questions /

Moderators: martimiz, Sean, Ed, biapar, Willr, Ingo, swaiba

many_many relationship (between "Task" and "Member") with editing in two places

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Community Member, 2 Posts

29 November 2016 at 9:03am

Edited: 29/11/2016 9:14am

Hi everyone

I've recently been working on understanding SilverStripe but I've encountered an issue I couldn't solve so far.

It basically involves 3 classes:

  • Task
  • Member Extension
  • MemberTask

The idea is to be able to have an editable list of tasks through TaskAdmin. When creating/editing a task through the TaskAdmin it should not only be possible to change name/description etc, but also to assign/remove them to/from a Member. (which is working)

The problem is that I also want to be able to see (and edit) the assigned Tasks when looking at a Member. This doesn't work and I'm not sure why.

My Task DataObject in its simplest form:

class Task extends DataObject

    private static $db = array (
        'Name' => 'Varchar',
        'Description' => 'Text',

    private static $has_one = array (
        'TaskImage' => 'Image'

    private static $many_many = array (
        'Members' => 'Member'

So far so good.

MyMemberExtension and TaskMember is where I don't seem to get it working:



class MyMemberExtension extends DataExtension {

    private static $many_many = array (
        'Tasks' => 'Task'

    public function updateCMSFields(FieldList $fields) {

        $source = Task::get()->map('ID','Title')->toArray();

        $fields->addFieldsToTab('Root.Main', array(
            ListBoxField::create('Tasks', 'Tasks')->setMultiple(true)->setSource($source)




class MemberTask extends DataObject

    private static $has_one = array (
        'Member' => 'Member',
        'Task' => 'Task',


    private static $belongs_many_many = array (
        'Members' => 'Member',
        'Task' => 'Task',



Anyone has an idea what I'm doing wrong? My suspicion is that I messed up MemberTask and the updateCMSFields in the Member Extension.