Show previous customer inputs in a form

My app has a form which user can access after login. They can fill up the options and once they click submit this data is saved to the database.

What I want to do is, next time they are on the same form, show them their choices from last time on the form and if they make any changes, new changes should be saved to the database along with the old changes.

I am able to do the first bit, show their choices from last time but if they make change to just one option and leave others untouched, only that option is saved to database and other fields show up as blank.

I don’t want to make the fields mandatory.

@wsu.app18 You can use autobinding where the user can modify select values rather than running a workflow to update the entire form

Do you have a guide on how to do that?