Recently I bumped into an error during Oracle APEX application import and I started digging in the depths of the APEX trying to figure out what the problem was. The error message stated that one foreign key constraint failed and I hoped to find a procedure with DML statement, where this error happened.
The error back trace was pretty long... and it ended at the COMMIT statement 😐At the COMMIT statement? And not at the very DML operation? 😮 I was puzzled... staring blankly at the screen... checking three times if I traced the error correctly... but I did. 😵
And suddenly I remembered that there is a parameter related to table constraints, the parameter I never used in my whole life, which determines if the constraint is validated at the moment of DML statement execution OR later on during the transaction ending COMMIT statement. This parameter is called "deferrable". And indeed, it was a case here. In the problematic APEX table all constraints were initially deferrable.
