title: Root property of a nested JSON or model in sencha
body: <p>i have a json in the following format: </p>
  
  <pre><code>{
   "collection": [
   {
    "id": 4, 
    "tickets": {
      "collection": [
        {
          "inner_id": 8,
        },
        {
          "inner_id": 10,
        }
      ],
      "count": 2,
      "type": "collection"
     },
    },
    {
    "id": 5, 
    "tickets": {
      "collection": [
        {
          "inner_id": 1,
        },
        {
          "inner_id": 2,
        }
      ],
      "count": 2,
      "type": "collection"
     },
    },
   ]
  }
  </code></pre>
  
  <p>For this particular JSON i created the models as:</p>
  
  <pre><code>Ext.define("myProject.model.ABC", {
  extend: "Ext.data.Model",
  config: {
      idProperty: "id",
      fields:[
          {name: "id", type: "int" },
      ],
      hasMany: [
          {
              model: "myProject.model.XYZ",
              name: "tickets",
              associationKey: "tickets",
          },
      ],
    }
  });
  </code></pre>
  
  <p>And second store as: </p>
  
  <pre><code>Ext.define("myProject.model.XYZ", {
  extend: "Ext.data.Model",
  config: {
      // idProperty: "id",
      fields:[
       {name: "inner_id", type: "int" },
  
      ],
       belongsTo: 'myProject.model.ABC'
   }
  });
  </code></pre>
  
  <p>But now i am confused. How do i populate the second store with a root property of collection again.</p>
  
  <p>I know one way is to easily change the json so that there is no collection child inside tickets but i dont want to do that. </p>
  
  <p>Any help would be appreciated. I have simplified the JSON for an easy example. </p>
  
  <p>EDIT:
  To be more clear, is there a way i can directly create a model which will read the Collection array inside the tickets object. </p>
  
  <p>EDIT: 
  Adding the store which populates the model ABC for more understanding </p>
  
  <pre><code>Ext.define("myProject.store.ABCs", {
  extend: "Ext.data.Store",
  config: {
      model: "myProject.model.ABC",
      autoLoad: false,            
      proxy: {
          type: "ajax",
          url: '',  //myURL
          reader: {
              type: "json",
              rootProperty: "collection",   // this is the first collection
          },
      },
  
   }
  });
  </code></pre>
  
  <p>This store loads the ABC model correctly but now i want to load the XYZ model which can load the inner array of collection</p>