the table doesn't change when modelData is changed

Hi all,

I create a table and bind JSONModel like this :

this.oModel = new sap.ui.model.json.JSONModel();

      this.oModel.setData({modelData:this.aData});

      this.oTable.setModel(this.oModel);

      this.oTable.bindRows("/modelData");

When I want to change value of existing rows, after setting new value, the modelData has changed , but there is no change in table rows .