How to process JSON data dynamically

Hello

I am representing data in JSON format.

oJSONData = {

                        showData: {

                                            sales_area_name : "Delaware" ,

                                           person                : "Dan"

                                        } ,

                                        0:{

                                            sales_area_name  :"wilmington",

                                           person               :" John"

                                           },

                    }

               }

i defined deep structure.

i set to model and to treetable.

how to process this dynamically after retriving sap.ui.getCore().getModel().getData();

i want to insert new values within this deep structure

Thanks