Problem with after delete trigger

I need help to solve a problem with a trigger.
I have TABLE_A (A_item1, A_item2, A_item3) and TABLE_B (B_item1, B_item2). B_item1 references foreing key to A_item1.

I have made a after delete trigger on TABLE_A to make something in another application.

My problem is that only need to run the code in the trigger when delete is ok processed. When foreing_key error deleting TABLE_A raised, I no have to make something

How can I know in after_delete trigger if the delete has been processed ok ???

Thanks