Question

Say I have have an instance of ModelA, which can ‘hasMany’ ModelB instances. Given the id for a ModelB record that already exists on the server, how do I associate model A with model B? (The API docs only show how to do this by simultaneously creating a new model B instance and database record.)

As an example, say I have an app that can be used schedule meetings with Person and Meeting objects. The server might return JSON like this for a meeting:

Meeting:

{
    id: '10',
    purpose: 'Code review',
    time: <timestamp>,
    attendees: [ 501, 532 ]
}

Person:

{ id: 501, name: 'Kermit', email: '[e-mail]' }

The models might be defined like this:

Ext.define('Person', {
    extend: 'Ext.data.Model',
    fields: ['id', 'name', 'email'],
    proxy: {
        type: 'rest',
        url : 'data/people',
        reader: { type: 'json' }
    }
});

Ext.define('Meeting', {
    extend: 'Ext.data.Model',
    fields: ['id', 'purpose', 'time'],
    hasMany: { model: 'Person', name: 'attendees' }
    proxy: {
        type: 'rest',
        url : 'data/meetings',
        reader: { type: 'json' }
    }
});

I understand that once a meeting is loaded. I can call meeting.attendees() to access each Person model. But, given new attendee ID (e.g., 599), how do I add another person to the meeting? Is the only option to load the Person instance for id 599 and then add the that instance to ‘attendees’, like this?

Meeting.load(10, {
    success: function(meeting) {

        Person.load(599, {
            success: function(person) {
                meeting.attendees().add(person);
                meeting.save();
            }
        });

    }
})

When meeting.save() runs, would the POST correctly include just the ID of the person, like this?

{
    id: '10',
    purpose: 'Code review',
    time: <timestamp>,
    attendees: [ 501, 532, 599 ] <-- '599' is new attendee
}

Thanks!

Answer 1

To be honest… associations are best used for reading. Editing associated models aren’t the best as there is no way to configure a writer or anything. For the UI, yes, add a new model to the store you get from attendees() but you need to also send that back to the server.