User Y. Yue indicated that the delete, update criteria is using filed = '' or field = null for a blank field which is incorrect. This one got me too as it has been a while. Turns out that you must set the dbNullText to blank (x.dbNullText="") such that if the field is blank it'll translate to [ is null ] instead of [ '' ] in the criteria. This is in the manual but not in bold letters. I updated the page and it should be clearer now.
Fk
