如何修改delphi自带数据库中表中字段的值

这一段代码没有提示错误但添加到数据库中的记录的值修改不了
procedure TForm3.Button1Click(Sender: TObject);

var
log,i:integer;
begin


try
with table1 do
begin
active;
open;
edit;
 log:=0;
 if edit1.Text=''then
    begin
     showmessage('请输入完整信息');
     exit;
    end;
 if edit2.Text='' then
    begin
     showmessage('请输入完整信息');
     exit;
    end;

for i:=0 to table1.fieldcount-1 do
  begin
  if table1.Eof=true then
     begin
     break;
     end;
  if table1.FieldByName('Goodsno').AsString=edit1.Text then
     begin

               log:=1;
               if table1.FieldByName('Goodsnum').AsInteger>=strtoint(edit2.Text) then
                   begin
                        table1.active;
                        table1.open;
                        table1.edit;
                        table1.FieldByName('Goodsnum').AsInteger:=table1.FieldByName('Goodsnum').AsInteger-strtoint(edit2.Text);
                        table1.Post;
                        table1.Close;
                        showmessage('出仓成功！');

                         exit;

                    end
               else

                    begin
                      showmessage('对不起！没有足够的货物');
                      table1.Close;
                      exit;
                    end;
       end;
       table1.Next;
  end;
   if  log=0 then
     begin
      showmessage('对不起！没有符合的产品');
      table1.Close;
      exit;
     end;
end;
 except;

end;
end;


procedure TForm3.Button2Click(Sender: TObject);
begin
close;
end;
 procedure TForm3.FormActivate(Sender: TObject);
begin
table1.Active;
table1.Open;
table1.Edit;
end;

end.