From: | Marko Tiikkaja <marko(dot)tiikkaja(at)cs(dot)helsinki(dot)fi> |
---|---|
To: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: assertions and constraint triggers |
Date: | 2010-08-11 07:54:00 |
Message-ID: | 4C625718.40609@cs.helsinki.fi |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 8/11/10 8:31 AM +0300, Peter Eisentraut wrote:
> Thinking about SQL assertions (check constraints that are independent of
> one particular table), do you think it would be reasonable to implement
> those on top of constraint triggers? On creation you'd hook up a
> trigger to each of the affected tables. And the trigger function runs
> the respective check expression. Conceptually, this doesn't seem to be
> very far away from foreign key constraints after all.
I thought the point of ASSERTIONs was that you could write a thing such as:
CREATE ASSERTION foo CHECK ((SELECT count(*) FROM tbl) = 4);
Enforcing that kind of constraints without true serializability seems
impractical.
Regards,
Marko Tiikkaja
From | Date | Subject | |
---|---|---|---|
Next Message | Simon Riggs | 2010-08-11 07:57:24 | Re: Bug / shortcoming in has_*_privilege |
Previous Message | Andres Freund | 2010-08-11 07:42:24 | Re: Cost of AtEOXact_Buffers in --enable-cassert |