add new row in the smart table

hello experts

in my project i need to add new rows in a smart table with editable data from json model , and then save data .

i used the binding context and CreateEntry but the smart table only shows data alredy existing in the backend .

when i debug i find the new data in the obindingContext but nothing is shown in the smart table .

this is my controller

var j = this.getView().getModel("oModeljson").getData();	
var tab = that.byId("smartTab");	
var oContext = new sap.ui.model.Context(that.oModel, "/entitySet");
 oContext =  that.oModel.createEntry("/entitySet", {
	properties: j[0]
		});
tab.setBindingContext(oContext);

also i am getting data in the getPendingChanges method.

my problem is how and add new row in a smart table ?

i dont now if i need to put my data in a metadata ?

actually i need to show only the new rows and not the existing data in the backend .

thank youu