Backbone-Relational related models not being created

问题

I'm trying to create a nested, relational backbone project but I'm really struggling. The rough idea of what I'm trying to do is shown below but I was under the impression upon calling fetch() on Client, a number of bookings would automatically be created based on the bookings being returned as JSON.

The format of my JSON can be seen beneath the outline of the MVC:

/****************************************************
/* CLIENT MODEL - Logically the top of the tree
/* has a BookingsCollection containing numerous Booking(s)                                                                             
/*  Client
/*      -Bookings               [BookingsCollection]
/*          -Booking            [Booking]
/*          -Booking            [Booking]
/*****************************************************/
var Client = Backbone.RelationalModel.extend({

    urlRoot: '/URL-THAT-RETURNS-JSON/',

    relations: [
        {
            type: Backbone.HasMany,
            key: 'Booking',
            relatedModel: 'Booking',
            collectionType: 'BookingsCollection'
        }
    ],

    parse: function (response) {

    },

    initialize: function (options) {
        console.log(this, 'Initialized');
    }

});


var Booking = Backbone.RelationalModel.extend({

    initialize: function (options) {
        console.log(this, 'Initialized');
    }

});

var BookingsCollection = Backbone.Collection.extend({

    model: Booking

});

Any help outlining what I'm doing wrong would be massively appreciated.

Thanks

EDIT

Thanks for taking the time to post the feedback, it's exactly what I was hoping for.

Is it the case that the JSON physically defines the actual attributes of models if you don't go to the effort of setting attributes manually? In other words, if the JSON I get back is as you have suggested above, would Backbone simply create a Client object (with the 4 attributes id, title, firstname & surname) as well as 2 Booking objects (each with 4 attributes and presumably each members of the BookingsCollection)?

If this is the case, what is the format for referencing the attributes of each object? When I set up a non-backbone-relational mini-app, I ended up in a situation whereby I could just reference the attributes using Client.Attribute or Booking[0].EventDate for example. I don't seem to be able to do this with the format you have outlined above.

Thanks again.

回答1:

The JSON being returned is not what Backbone or Backbone-Relational is expecting by default.

The expectation of Backbone and Backbone-Relational is:

{
    "id": "123456",
    "Title":"Mr",
    "FirstName":"Joe",
    "Surname":"Bloggs",
    "Bookings": [
        {
            "id": "585462542",
            "EventName": "Bla",
            "Location":"Dee Bla",
            "EventDate":"November 1, 2012"
        },
        {
            "id": "585462543",
            "EventName": "Bla",
            "Location":"Dee Bla",
            "EventDate":"November 1, 2012"
        }
    ]
}

To use your response, you need to create a parse function on the Client model that returns the structure I've posted above.

A jsFiddle example of your model definitions working with my example JSON: http://jsfiddle.net/edwardmsmith/jVJHq/4/

Other notes

• Backbone expects ID fields to be named "id" by default. To use another field as the ID for a model, use Model.idAttribute
• The "key" for the Bookings Collection I changed to "Bookings"

Sample Code:

Client = Backbone.RelationalModel.extend({

    urlRoot: '/URL-THAT-RETURNS-JSON/',

    relations: [
        {
            type: Backbone.HasMany,
            key: 'Bookings',
            relatedModel: 'Booking',
            collectionType: 'BookingsCollection'
        }
    ],

    parse: function (response) {

    },

    initialize: function (options) {
        console.log(this, 'Initialized');
    }

});


Booking = Backbone.RelationalModel.extend({

    initialize: function (options) {
    console.log(this, 'Initialized');
    }

});

BookingsCollection = Backbone.Collection.extend({

    model: Booking

});

myClient = new Client(    {
        "id": "123456",
        "Title":"Mr",
        "FirstName":"Joe",
        "Surname":"Bloggs",
        "Bookings": [
            {
                "id": "585462542",
                "EventName": "Bla",
                "Location":"Dee Bla",
                "EventDate":"November 1, 2012"
            },
            {
                "id": "585462543",
                "EventName": "Bla",
                "Location":"Dee Bla",
                "EventDate":"November 1, 2012"
            }
        ]
    });


console.log(myClient);​

Post Edit

Yes, the JSON pretty much defines the attributes of the model. You can use a combination of parse(), defaults, and validate() to better control what attributes are valid and allowed.

The canonical way of reading and setting properties on a Backbone Model is through the get(), escape(), and set() functions.

set is especially important as this does a bunch of housekeeping, such as validating the attribute and value against your validate function (if any), and triggering change events for the model that your views would be listening for.

In the specific case of the situation in this answer, you might

myClient.get('Title');  // => "Mr"
myClient.get('Bookings'); //=> an instance of a BookingsCollection with 2 models.
myClient.get('Bookings').first().get('Location'); //=> "Dee Bla"
myClient.get('Bookings').last().get('Location');  //=> "Dee Bla"
myClient.get('Bookings').first().set({location:"Bora Bora"}); 
myClient.get('Bookings').first().get('Location'); //=> "Bora Bora"
myClient.get('Bookings').last().get('Location');  //=> "Dee Bla"

来源：https://stackoverflow.com/questions/11316782/backbone-relational-related-models-not-being-created