This is the fields in the database, with the GUID's I have provided



This is the fields in the Form which show no document as being selected

It is possible but why don't you use the API to perform your updates vs. directly accessing the database? There could be a number of different problems with your direct database approach where a simple API call would resolve this. For instance, updates in more than one place, validation, cascading deletions, etc.

So even though you can query the database, I'd highly recommend staying away from it unless you know all the objects that will or are going to be updated.