Question

当我创建一个新的json模型时，我遇到了一些麻烦，嵌套属性应该被解析为一个集合。在这里，我展示了如何得到错误：

（感谢任何帮助）

1）我创建了一个像这样的用户

user = new App.Models.User( {"email":"tom@gmail.com","id":1,"user_cities_attributes":[{"city_id":431,"user_action":"to-visit","user_id":1}] }

2）然后我在控制台检查发生了什么，集合没有被创建。：S

user.get('user_cities')
> undefined # where is my collection?! :(
user.get('user_cities_attributes')
> [Object] # mmm weird...

如果我尝试将新模型添加到集合中......

cities = new App.Collections.CitiesCollection()
cities.fetch()

userCity = new App.Models.UserCity( { user: user, city: cities.first(), user_action: "to-visit" } )

现在一切似乎都很好......发生了什么????

user.get('user_cities')
> Backbone.Collection {length: 20, models: Array[20], _byId: Object, model: function, user: User…}
user.get('user_cities_attributes')
undefined

模型

class App.Models.User extends Backbone.RelationalModel
  paramRoot: 'user'
  urlRoot: 'users'

  defaults:
    name: null

class App.Models.UserCity extends Backbone.RelationalModel
  paramRoot: 'user_city'
  urlRoot: 'user_cities'

  defaults:
    user_action: null

  relations: [{
    type: Backbone.HasOne,
    key: 'user',
    relatedModel: 'App.Models.User',
    collectionType: 'App.Collections.UsersCollection',
    keySource: 'user_id',
    includeInJSON: 'id',
    reverseRelation: {
      key: 'user_cities',
      keySource: 'user_cities_attributes',
      includeInJSON: 'id'
    }
  },
  {
    type: Backbone.HasOne,
    key: 'city',
    relatedModel: 'App.Models.City',
    collectionType: 'App.Collections.CitiesCollection',
    includeInJSON: 'id',
    keySource: 'city_id',
    reverseRelation: {
      key: 'users',
      includeInJSON: 'id'
    } 
  }]

class App.Models.City extends Backbone.RelationalModel
  paramRoot: 'city'
  urlRoot: 'cities'

  defaults:
    name: null

  relations: [{
    type: Backbone.HasMany,
    key: 'places',
    relatedModel: 'App.Models.Place',
    collectionType: 'App.Collections.PlacesCollection',
    keySource: 'places_attributes',
    # parse: true,
    includeInJSON: 'id',
    autoFetch: true,
    reverseRelation: {
      key: 'city',
      includeInJSON: 'id'
    }
      # 'relatedModel' is automatically set to 'Zoo'; the 'relationType' to 'HasOne'.
  }]

Answer 1

查看有关reverseRelation的注释并使用coffeescript（来自：http://backbonerelational.org/#relations-reverseRelation）：

请注意，如果在a上定义关系（加上reverseRelation）模型，但实际上并没有创建该模型的实例，它是可能的initializeRelations永远不会被调用，而且 reverseRelation不会被初始化。扩展时会发生这种情况已被覆盖，或在CoffeeScript中重新定义。见设置。

然后尝试使用.setup，如下所述：http://backbonerelational.org/#RelationalModel-setup

嵌套集合创建为数组而不是集合

1 个答案: