创建具有主干关系的嵌套结构答案

【问题标题】：creating nested structure with backbone-relational创建具有主干关系的嵌套结构
【发布时间】：2016-10-12 09:42:51
【问题描述】：

我正在尝试创建三个级联下拉列表。第一个包含项目，第二个包含选定项目的任务，最后一个包含选定任务的站点。

我想使用 Backbone-Relational 插件，但很难创建正确的关系。这是我第一次使用这个插件。

到目前为止的代码：

App.Models.ProjectItem = Backbone.RelationalModel.extend({
    default: {
        id: 0,
        name: ''
    },
    relations: [{
        type: Backbone.HasMany,
        key: 'tasks',
        relatedModel: App.Models.TaskItem,
        //includeInJSON: Backbone.Model.prototype.idAttribute,
        collectionType: App.Collections.TasksCollection,
        reverseRelation: {
            key: 'projectId',
            //includeInJSON: Backbone.Model.prototype.idAttribute,
            type: Backbone.HasOne
        }
    }]
});

App.Collections.ProjectsCollection = Backbone.Collection.extend({
    model: App.Models.ProjectItem
});

App.Models.TaskItem = Backbone.RelationalModel.extend({
    default: {
        id: 0,
        name: ''
    },
    relations: [{
        type: Backbone.HasMany,
        key: 'sites',
        relatedModel: App.Models.SiteItem,
        includeInJSON: Backbone.Model.prototype.idAttribute,
        collectionType: App.Collections.SitesCollection,
        reverseRelation: {
            key: 'taskId',
            //includeInJSON: Backbone.Model.prototype.idAttribute,
            type: Backbone.HasOne
        }
    }]
});

App.Collections.TasksCollection = Backbone.Collection.extend({
    model: App.Models.TaskItem
});

App.Models.SiteItem = Backbone.RelationalModel.extend({
    default: {
        id: 0,
        name: ''
    }
});

App.Collections.SitesCollection = Backbone.Collection.extend({
    model: App.Models.SiteItem
});

创建单个项目：

var item = new App.Models.ProjectItem({
  id: 1,
  name: 'project',
  tasks: [
    {
      id: 1,
      name: 'task',
      sites: [
        {
          id: 1,
          name: 'site'
        }
      ]
    }
  ]
})

这个序列化为 json 的对象如下所示：

"{"id":1,"name":"task","tasks":[1],"sites":[{"id":1,"name":"site"}],"projectId":null}"

我的问题：

1) 为什么站点数组没有嵌套在任务一中？

2) 网站集的序列化方式与任务一不同。我也应该在站点模型中创建关系吗？

3) 为什么会为根返回 projectId？

【问题讨论】：

标签： backbone.js backbone-relational

【解决方案1】：

经过数小时的反复试验，我终于明白了。顺序很重要。。工作代码：

App.Models.SiteItem = Backbone.RelationalModel.extend({
    default: {
        siteId: 0,
        name: ''
    }
});

App.Collections.SitesCollection = Backbone.Collection.extend({
    model: App.Models.SiteItem
});

App.Models.TaskItem = Backbone.RelationalModel.extend({
    default: {
        taskId: 0,
        name: ''
    },
    relations: [{
        type: Backbone.HasMany,
        key: 'sites',
        relatedModel: App.Models.SiteItem,
        //includeInJSON: Backbone.Model.prototype.idAttribute,
        collectionType: App.Collections.SitesCollection,
        reverseRelation: {
            key: 'task',
            includeInJSON: 'taskId',
            type: Backbone.HasOne
        }
    }]
});

App.Collections.TasksCollection = Backbone.Collection.extend({
    model: App.Models.TaskItem
});

App.Models.ProjectItem = Backbone.RelationalModel.extend({
    default: {
        projectId: 0,
        name: ''
    },
    relations: [{
        type: Backbone.HasMany,
        key: 'tasks',
        relatedModel: App.Models.TaskItem,
        //  includeInJSON: 'taskId',
        collectionType: App.Collections.TasksCollection,
        reverseRelation: {
            key: 'project',
            includeInJSON: 'projectId',
            type: Backbone.HasOne
        }
    }]
});

App.Collections.ProjectsCollection = Backbone.Collection.extend({
    model: App.Models.ProjectItem
});

对于样本数据：

var item = new App.Models.ProjectItem({
  projectId: 2,
  name: 'first',
  tasks: [
    {
      taskId: 1,
      name: 'task',
      sites:[{siteId:1, name: 'site'}]
    }
  ]
});

我得到了这个 json 字符串：

"{"projectId":2,"name":"first","tasks":[{"taskId":1,"name":"task","sites":[{"siteId":1,"name":"site","task":1}],"project":2}]}"

【讨论】：