Re: Trigger help - updates to column data with null values
| От | Greg Fischer |
|---|---|
| Тема | Re: Trigger help - updates to column data with null values |
| Дата | |
| Msg-id | c16a72fa1003022028v63f6abc6pe4c3f74e0c10170d@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Trigger help - updates to column data with null values (Craig Ringer <craig@postnewspapers.com.au>) |
| Список | pgsql-general |
NICE!!! Worked beautifully! I figured NULL's were not evaluating as a value, but I didn't have the correct operators:
Greg Fischer
www.1stbyte.com
these constructs effectively act as though null were a normal data value, rather than “unknown”.
I guess I wasn't reading the right part of the manuals! LOL! Thanks so much!
Greg Fischer
www.1stbyte.com
On Tue, Mar 2, 2010 at 8:07 PM, Craig Ringer <craig@postnewspapers.com.au> wrote:
Greg Fischer wrote:Instead, try the test:
> Hello all!
> I do my best to read and google my way around issues, but I seem to be
> missing something. Probably simple too.
>
> So I have a trigger function, in which I'd like to check if a particular
> column has changed. It works great, unless either the OLD or NEW values
> are NULL. The purpose is to create a audit/log of the record. I prefer
> to only test for certain columns, not the whole table.
>
>
> CREATE OR REPLACE FUNCTION tr_employees_bu()
> RETURNS trigger AS
> $BODY$
> begin
> if (new.trainingdate <> old.trainingdate) then
new.trainingdate IS DISTINCT FROM old.trainingdate
See the manual for 'IS DISTINCT FROM'.
--
Craig Ringer
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