Querying a multi-record block within my form

Question

I have a form where I perform validations of items entered on my main block. I compare the item value entered to an expected value and if they are different then an exception record must be created in a separate, multi-record block within my application. One record on my main block may end up with multiple different exception records in the multi-record block. As a result, part of my validation must include determining whether the user has already created an exception record for the item that I'm validating in the multi-record block.
Is there a way for me to query and uncomitted, multi-record block in my form? Help would be greatly appreciated!

Answer 1

Andreas' method is good.
Only several changes:
  LOOP... EXIT WHEN :SYSTEM.RECORD_STATUS='NEW';
(Use NEW, not TRUE)
And just before the Raise Form_Trigger_Failure, I would Go_Item to either the item in error, or to a new line in the exceptions block. And also issue an error message.
....By the way...
If your exceptions block has more rows than will fit on the screen, then your search loop function will may cause the rows to jump up or down when the user tries to commit. There is a way to reset the view after the function completes its search -- you just need to store the value of the block's Top_Record property before the First_Record command, and then Go_Record(Top_Rec_value); after the function completes its loop.
Also, there is a way to prompt the user to enter the exception record when you first validate the item in a when-validate-item trigger. But the user might ignore the prompt, so you still need to re-check everything from the key-commit process. To use the WVI prompting, in the WVI trigger you check if an exception is required. If it is, store the item name in a package variable, then start a non-repeating timer. When the timer expires, save the :System.cursor_item value (so you can go_item back to it after calling the function), and then call the function to check for the exception for the item named in the package variable. If not found, prompt the user. If found, go_item back to the cursor_item_value.