Ember-data building relationships without ids - ember-data

Question

I'm trying to build an Ember application with a MongoDB backend. Ember-data now supports embedded objects which makes it really easy and great to be able to pull the objects right out of the nested document.
My problem is in figuring out how to relate objects to each other.
Lets look at an example of a class room with students and assignments.
{
students: [
{ name: 'Billy' },
{ name: 'Joe' }
],
assignments: [
{ name: 'HW1', score: 70, student_name: 'Billy' },
{ name: 'HW2', score: 80, student_name: 'Billy' },
{ name: 'HW1', score: 60, student_name: 'Joe' },
{ name: 'HW2', score: 75, student_name: 'Joe' }
]
}
How would I build a relationship for the student so that I could pull back all of their assignments?
Related, I'm trying to figure out how to relate objects that are nested inside each other. I created a jsbin trying to build a relationship between nested objects (going up the tree rather than just down) but I'm not sure how to do it.

Answer 1

You can use the repo below to guide you on how to do embedded association. Though they are not using mongodb, the important thing is on the ember-data side, they are doing embedded association.
https://github.com/dgeb/ember_data_example/blob/master/app/assets/javascripts/controllers/contact_edit_controller.js
Note that here App.PhoneNumber is embedded in App.Contact. But it should give you an idea on how to go abut resolving yours.
App.Contact = DS.Model.extend({
firstName: DS.attr('string'),
lastName: DS.attr('string'),
email: DS.attr('string'),
notes: DS.attr('string'),
phoneNumbers: DS.hasMany('App.PhoneNumber'),
});
App.PhoneNumber = DS.Model.extend({
number: DS.attr('string'),
contact: DS.belongsTo('App.Contact')
});
https://github.com/dgeb/ember_data_example/blob/master/app/assets/javascripts/store.js
App.Adapter = DS.RESTAdapter.extend({
bulkCommit: false
});
App.Adapter.map('App.Contact', {
phoneNumbers: {embedded: 'always'}
});
App.Store = DS.Store.extend({
revision: 12,
adapter: App.Adapter.create()
});
https://github.com/dgeb/ember_data_example/blob/master/app/assets/javascripts/controllers/contact_edit_controller.js
App.ContactEditController = Em.ObjectController.extend({
needs: ['contact'],
startEditing: function() {
// add the contact and its associated phone numbers to a local transaction
var contact = this.get('content');
var transaction = contact.get('store').transaction();
transaction.add(contact);
contact.get('phoneNumbers').forEach(function(phoneNumber) {
transaction.add(phoneNumber);
});
this.transaction = transaction;
},
save: function() {
this.transaction.commit();
},
addPhoneNumber: function() {
this.get('content.phoneNumbers').createRecord();
},
});