Re: DEFERRABLE NOT NULL constraint

Thomas Kellerer <spam_eater@gmx.net>

From: Thomas Kellerer <spam_eater@gmx.net>
To: pgsql-general@postgresql.org
Date: 2013-02-05T10:31:49Z
Lists: pgsql-general
Andreas Joseph Krogh, 05.02.2013 11:15:
>     Andreas Joseph Krogh, 05.02.2013 10:57:
>      > The value of having NOT NULL deferrable is, well, to not check for
>      > NULL until the tx commits. When working with ORMs this often is the
>      > case, especially with circular FKs.
>
>     With circular FKs it's enough to define the FK constraint as deferred.
>
> I meant; circular FKs which are also NOT NULL

A deferrable FK is still enough for that scenario as you can insert FK values that do not yet exist.

See Alban's answer for an example.