Getting and setting the default Model once another has been setup - sapui5

Question

My issue is that I have a default model specified in my manifest.json file as "".
However, I'm also setting up a view model in my controller.
var oModel = new JSONModel({
questions: [{
order: 1,
title: "",
criteria: "",
}]
});
this.getView().setModel(oModel);
How do I restore set the view model back to the default model?
Is it simply a case of
this.getView().setModel("");
I'm asking because the default model is the service that contains all my read/writes.

Answer 1

You should set named models after setting the default model.So your code should be changed like
var oModel = new JSONModel({
questions: [{
order: 1,
title: "",
criteria: "",
}]
});
this.getView().setModel(oModel,"newModelName");
Now you can get default model by
this.getView().getModel()
and named json model by
this.getView().getModel("newModelName");

Answer 2

The solution was in the way the additional model was initialised and accessed, but naming it and referring to it as 'viewmodel'
This way, the default model can still be setup using
oModel = this.getView().getModel();
In the Controller:
this.getView().setModel(oModel,"viewmodel");
var oContext = oModel.createBindingContext("/questions/0/");
this.getView().setBindingContext(oContext,"viewmodel");
In the view :
title="Question {viewmodel>order}"