Try checking the "null for identities" checkbox. I think this functions as "ignore ID column". This assumes your field_1 above is an ID.
If that doesn't work, using a Query/Script component (vs a set of Table generator comps) is an option here... your SQL would just be something like:
UPDATE mytable SET mycolumnhere = @blah WHERE myid = @yadda
Above, blah would be the updated value, and yadda would be some ID to identify what row to update