My question is say you ran a daycare and had a table for the children and another for their related school (with the FK in the child table), if the school of some of the children, for some reason, closed down, and you had the On Delete option set to SET NULL, would this make sense and also, could you then update the related foreign key to their new school or how would you address this?
SHOW CREATE TABLE
for both tables if you want further help. – Rick James Jul 25 '20 at 19:16