Web App Popup showing related external source data

[DavinShokes1]

Does anyone know of a web app example where popups show a relationship between the feature layer and external data? For instance, connecting editable values in a popup or custom widget  to a Google sheet, fusion table, or a SQL Web Service. Adding a new feature triggers external row creation and future updates are possible due to the related field.

I'm more comfortable with JavaScript, but really an example in any language would be great!

Thanks,

Davin