Re: insert trigger - Mailing list pgsql-admin

From Marc Mitchell
Subject Re: insert trigger
Date
Msg-id 004301c28677$b40ee360$e802010a@crosscountrycourier.com
Whole thread Raw
In response to insert trigger  ("Roberto Benitez" <RBENITEZ@houston.rr.com>)
List pgsql-admin
It would appear to me that you are really doing this the hard way.

If you are trying to set/change fields in the same row that you are
inserting (say to force an add date or userid) you could use an INSTEAD
rule to transform the insert passing through the fields you don't wish to
change and transforming the ones that you do.  You turn what would be 3
statements into one.  I think an alternative to this would also be a BEFORE
INSERT trigger and function as I believe the function can simply change the
current values of the row before the insert takes place.

If you are trying to set/change fields in another table based on the values
of the row inserted, then the rule should have access to NEW. attributes
for the columns and their inserted values and there is no need for you to
go out searching (SELECTing) for them.

Hope this helps,

Marc Mitchell - Senior Application Architect
Enterprise Information Solutions, Inc.
Downers Grove, IL 60515
marcm@eisolution.com


----- Original Message -----
From: "Roberto Benitez" <RBENITEZ@houston.rr.com>
To: <pgsql-admin@postgresql.org>
Sent: Monday, November 04, 2002 9:05 PM
Subject: [ADMIN] insert trigger


I have the following situation:

    when a new record is inserted in to a psql table, i want to be able to
update certain fields.  the way i'm doing it right now..to find the last
record inserted...is by sorting the primary key (serial) in descending
order and taking the first item in the list...the one at the top should be
the one i just entered...and of course, i then procede to update the
fieldsd i need to update..
So, basically would like to know if this will always work.  will the one at
the top (the one w/ the highest primary key [serial type]) always be the
one i just entered. AND does psql ALWAYS execute the trigger(s) after EVERY
single record that is inerted. what would happen if [ n ] different users
try to insert records simultaniously? will psql insert one-execute the
trigger, insert the next-execute the trigger..and so on? or will it insert
ALL [n] records AND THEN  execute the trigger?

i would appreciate any advice--if this would work, or if there is a better
way.

thanks
rbenitez22@yahoo.com








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