Alert to be fired only for first record when duplicate entries exist

Question

Hello,
This is related to Oracle forms 10g.
I have a multi record block wherein I am entering and storing some codes, something like below
Code Description
=====================
ABCD AAAAAAAAAAAA
PQRS BBBBBBBBBBBBB
DDDD SSSSSSSSSSS
ABCD DHGFKSDHKSHG
PQRS DFJHHGS
EEEE SDT85604ET
=====================
Now I need to display an alert/msg from when-validate-item of the Code field. So now if I am on first record, the alert/msg will be displayed for code ABCD which is Ok. Now on next record I enter a different code PQRS as given above, the alert will again be displayed which is Ok. If I enter a code which was previously entered in the multi record block and alert/msg had been displayed at that first time, the alert/msg need not be displayed now again i.e. if I enter ABCD again in fourth record, the alert should not be displayed.
Note that this need to be done at the data entry time itself. I guess may be it can be done using record groups/ plsql table.
Any help with a way to solve this issue will be highly appreciated..
Thanks and Regards...

Answer 1

As you have already guessed, you have to be able to keep track of how many times a value has been entered. If you know what all of the possible "CODE" values are at design-time, you could create a counter variable for each value, but this would be a total pain. A better solution would be to keep a dynamic running total that you can quickly check against. For this I recommend you use a Forms Record Group. Take a look at the Forms - Record Group Processing (Duplicate Value Checking) demo I wrote. Using the Forms Rec_Group package provided in this demo, you could easly modify the process listed in the document to work in your scenario. Follow all of the steps in the demo. For your situation, you will need to modify the When-Validate-Item trigger so that instead of checking for dupicates and failing the form if a duplicate is found, you will check the number of entries for a value in the record group and display a message if the count is 0 or not display a message if the count is greater than 0. Your modified WVI trigger might look like this:
DECLARE
   ignore     NUMBER := 0;
   bignore   BOOLEAN := FALSE;
BEGIN
   IF ( :YOUR_BLOCK.CODE IS NOT NULL ) THEN
      ignore := Rec_Group.Get_Number(Rec_Group.rg_name, :YOUR_BLOCK.CODE);
      IF ( ignore = 0 ) THEN
          -- Display your message
      ELSE
          -- Don't display any message
      END IF;
      /* add the code to the record group */
      bIgnore := Rec_Group.Add_Value(rec_group.rg_name, :YOUR_BLOCK.CODE, :system.trigger_record);
   END IF;
END;Hope this helps,
Craig B-)
If someone's response is helpful or correct, please mark it accordingly.
Edited by: CraigB on Mar 30, 2011 3:07 PM