I'd like to create a checkbox that would replace the current filename in he db with null.
I don't care if the file stays on he server. I just do not want it displayed on the details page.

Here is what I have so far (it does not even write the word null into the db):
<input <?php if (!(strcmp($row_updatefac['syllabus6'],"null")) {echo "checked=\"checked\"";} ?> name="syllabus6" type="checkbox" value="NULL" />