Hello. Yes, just update the field with a new value. If everything is done properly, calling CloudSet on the same field for the same student overrides the previous value, not adds a new row to the table. Just like in the demo https://cluelabs.com/widget-demos/data-cloud/index.html every time you click on the markers 1-4, the field value is updated.

Each user can access only his/her own data, this was done to ensure data security. However, you can request this custom feature through premium widgets http://cluelabs.com/stencil/widget-premium that will be available only to you (your organization).

Hi again. We had an internal discussion and concluded that it would be nice to add a feature like you described to the basic Data Cloud widget. You should see it later this week or early next week. Thank you for the suggestion!