Best practice for loading non model data in ExtJS

Question

Let's assume that I have 2 tables in my database, a user table and a folder table. They are matched by two models (beans) in my backend java code and similarly by to models in my extjs client side. Using viewmodel architecture, I want to create a form that shows the username and the amount of folders they have created using viewmodel bindings. Each folder in the database has a CREATE_USER_ID field that contains the id of the user that created the folder. How do I go about loading the required data?

Answer 1

Viewmodels are not designed to load data directly (and not designed to load non model data at all). You've got two options:

1. Go model (recommended). Two sub-options:
   • Add folder_amount field to your client side user model. On the server side this does not necessarily need to be added as well as you can adjust your API feeding data to client to add that field dynamically.
   • If you want to keep your client models exactly matching their server mates, use viewmodel in conjunction with associations (see example here, scroll down to Associations) to load folders themselves, though in the UI only show the amount of them. Mind that you don't need to load all folder fields but just their IDs.
2. Stick to your own fancy non model approach, but this won't have anything to do with viewmodel bindings. This may be, for example, making an AJAX call to retrieve the number of folders when user data is rendered in the UI.