Re: deferrable foreign keys

Morus Walter <morus.walter.ml@googlemail.com> writes:
> are there downsides of making foreign keys deferrable (but initially
> immediate) for updates, when the transaction does not set the
> constraint behaviour to deferred?

> I'd expect that to have the same behaviour as non deferrable foreign
> keys.
> What I don't understand is, why is non deferrable the default, then.

Because the SQL standard says so.  I don't believe there is any actual
penalty for deferrable within the PG implementation, but perhaps there
is in other systems' implementations.

            regards, tom lane