FRAME CHALLNAGE

Your first three lines of the question raise massive red flags for me. If you have to disable the foreign key constraiant before doing a delete then you are at high risk of leaving orphaned records after your delete completes.

There might be a reason to do this but I have never seen a use case where you would want to disable a fK-Constraint on the fly, triggers yes but constraints no.

I would be questioning the new applciation behaviour quite closely before even attempting this.