Re: CASCADE/fkey order

I checked, and changing the `bazinga_foo_bar` constraint to:

alter table bazinga add constraint bazinga_foo_bar foreign key (foo_id,
bar_id) references foo_bar (foo_id, bar_id) deferrable initially deferred;

seems to fix it to work as we were expecting. Is that particularly
costly? Should I only set the constraint to be deferred when we really
need it? Would it be more efficient to perform the deletes explicitly
within a transaction rather than relying on the cascades and deferring that
one constraint?

Our resident ex-Oracle DBA said that deferred constraints used to be
heavily recommended against, but he also admitted that he hasn't kept up
with that in the past 10 years.

-Sam

https://github.com/nelsam

"As an adolescent I aspired to lasting fame, I craved factual certainty, and
I thirsted for a meaningful vision of human life -- so I became a scientist.
This is like becoming an archbishop so you can meet girls."
-- Matt Cartmill

On Wed, Jul 22, 2020 at 10:31 AM David G. Johnston <
david(dot)g(dot)johnston(at)gmail(dot)com> wrote:

> On Wed, Jul 22, 2020 at 8:24 AM Samuel Nelson <valczir(dot)darkvein(at)gmail(dot)com>
> wrote:
>
>> Is there a way to force the delete to cascade to tables in a specific
>> order?
>>
>
> No really, but you can defer constraint checking.
>
> https://www.postgresql.org/docs/12/sql-set-constraints.html
>
> David J.
>
>