From: | Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec> |
---|---|
To: | Christophe Pettus <xof(at)thebuild(dot)com> |
Cc: | Andrus <kobruleht2(at)hot(dot)ee>, pgsql-general(at)postgresql(dot)org |
Subject: | Re: How to use read uncommitted transaction level and set update order |
Date: | 2009-12-28 15:38:41 |
Message-ID: | 3073cc9b0912280738s45512326p5ce21a097776a855@mail.gmail.com |
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Thread: | |
Lists: | pgsql-general |
On Sat, Dec 19, 2009 at 7:16 PM, Christophe Pettus <xof(at)thebuild(dot)com> wrote:
>
>> I understand that it is not possible to read previous rows without
>> creating hack using triggers.
>
> As noted above, that's not correct. You cannot access new values of a
> particular row within a single UPDATE statement, but you do see new values
> done in the same transaction.
>
what´s the problem with something as simple as:
create function keep_a_in_b_test1() returns trigger as $$
begin
new.b = old.a;
return new;
end;
$$ language plpgsql;
create trigger trg_keep_a_in_b_test1 before update
on test1 for each row execute procedure keep_a_in_b_test1();
--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157
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