Testing if an image is null

Question

Hi guys,
Was wondering if you could help me out. I have a data block based on a table, and this table contains an image of type blob. Now, I have some items on my form that I only want to display if the image is not null and was wondering how I could accomplish this. I dont think the following will work:
if myblock.picture is not null then
end if
Am I correct in thinking that would not work because it cant check if an image is null or not?
I know I could create a view and add a column using a case statement as follows:
case when myblock.picture is null then 'N' else 'Y' end picture_present
However, I am reluctant to create such a view and change my form on it (as my datablock is simply based on a table). I was wondering could I create an item on my datablock which would effectively add the picture_present column I would have had on my view? ie using the formula property on an item? (I ask this because I have never used this column before). So basically, could I create an item and input to the formula property:
case when iph.picture is null then 'N' else 'Y' end picture_present
and then this item would evaluate to 'Y' if there was a picture and 'N' if there was not?
if this wont work could anyone suggest away around my problem.
Thanks for any time you may take in helping me.
Edited by: 786733 on 30-Jul-2012 02:44

Answer 1

You could check if the blob is empty in a post-query trigger like this
declare
  dummy number;
begin
  select 1
  into ndummy
  from your_table
  where your_pk = :block.your_pk
  and length(your_blob) > 0;
  do_something_when_not_empty;
exception
  when no_data_found then
    do_something_when_empty;
end;cheers