Dear specialists,

I'm writing a program in delphi 7 that reads and writes data from and to a ms access database via an ADOQuery.

ADOQuery.edit;
ADOQuery.fieldbyname('integerfield').AsInteger:=fo rm.editbox.text;
ADOQuery.post;

This thing works, however, when I need to put in a null value in the database, I got a problem

ADOQuery.edit;
if form.editbox.text>0 then
ADOQuery.fieldbyname('integerfield').AsInteger:=fo rm.editbox.text
else
ADOQuery.fieldbyname('integerfield').AsInteger:=Nu ll; (*doesn't work*)
ADOQuery.fieldbyname('integerfield').IsNull:=True; (*doesn't work*)
ADOQuery.fieldbyname('integerfield').Clear; (doesn't work*)
ADOQuery.fieldbyname('integerfield').Whattodohere?
ADOQuery.post;

Looking forward for a solution