Re: triggers: how to check if a field changed?
| От | Lance Arlaus |
|---|---|
| Тема | Re: triggers: how to check if a field changed? |
| Дата | |
| Msg-id | 000b01c5ad1a$df752b00$6401a8c0@LanceLaptop обсуждение исходный текст |
| Ответ на | triggers: how to check if a field changed? (<me@alternize.com>) |
| Список | pgsql-novice |
The following assumes you're writing the trigger in PL/pgSQL, but there are similar facilities in the other supported langs.
There are two records (OLD and NEW) that are pre-defined in trigger procedures. Simply compare the fields on those records.
For example (assuming field is non-nullable):
IF (OLD.p_msg_raw <> NEW.p_msg_raw) THEN
-- Reindex
ENDIF
-----Original Message-----
From: pgsql-novice-owner@postgresql.org [mailto:pgsql-novice-owner@postgresql.org] On Behalf Of me@alternize.com
Sent: Monday, August 29, 2005 8:47 PM
To: pgsql-novice@postgresql.org
Subject: [NOVICE] triggers: how to check if a field changed?hi listfor our discussion board i've successfully set up a trigger to have tsearch2 index the record every time it is updated. this works fine, but also triggers the reindex of the record every time i update the "# of views" counter, which creates unnecessary load. in a trigger, is there a way to check the fields affected by the UPDATE query? i only want to have the tsearch2 index updated when the indexed field (p_msg_raw) changed...this is the current trigger (straight following the tsearch2 guide):CREATE TRIGGER "posts_ts_update" BEFORE INSERT OR UPDATE
ON "forum"."posts" FOR EACH ROW
EXECUTE PROCEDURE "public"."tsearch2"(idxfti, p_msg_raw);thanks in advance,thomas
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