Commit rules or Commit trigger

On Apr 24, 2006, at 9:37 AM, Claudio Tognolo wrote:

I am developing a temporal database and I have the necessity to
control the integrity constraints befor the commit of the transiction.
I cannot use the deferrable checking because the integrity
constraints is a select and i cannot use the trigger or rule because
the event parameter not support the commit event.
You have some idea?

My understanding is that deferred constraints are not checked until
commit time, which seems to be what you want. Why do you believe
otherwise?

On Thu, Apr 27, 2006 at 10:17:51 -0400,
Vivek Khera <vivek@khera.org> wrote:

On Apr 24, 2006, at 9:37 AM, Claudio Tognolo wrote:

I am developing a temporal database and I have the necessity to
control the integrity constraints befor the commit of the transiction.
I cannot use the deferrable checking because the integrity
constraints is a select and i cannot use the trigger or rule because
the event parameter not support the commit event.
You have some idea?

My understanding is that deferred constraints are not checked until
commit time, which seems to be what you want. Why do you believe
otherwise?

But you aren't really allowed to do selects in constraints even though you
can make Postgres do that in a way that partly works. You need to enforce
these constraints with an after trigger.