From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
---|---|
To: | Thiemo Kellner <thiemo(at)gelassene-pferde(dot)biz> |
Cc: | "pgsql-general(at)lists(dot)postgresql(dot)org" <pgsql-general(at)lists(dot)postgresql(dot)org> |
Subject: | Re: Detection of which attributes should get set in update trigger |
Date: | 2023-11-10 13:35:01 |
Message-ID: | CAKFQuwaKwWecLH7fchrm-0hn-LKR6c3ki4C9x8dR0BRM+itueg@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Friday, November 10, 2023, Thiemo Kellner <thiemo(at)gelassene-pferde(dot)biz>
wrote:
> Hi all
>
> I have a view, that is a join over 4 tables (the setup of the rule
> question). I want to update the central table over the view (by an
> instead-of trigger). How can I determine, whether an attribute should get
> set to NULL, "new.XYZ is null" or whether it should be left alone. Is there
> a leave-me-alone function determining, whether an attribute is in the set
> clause of an update statement. I am thinking along the line code in the
> trigger function like
>
> update TABLE
> set XYZ = case
> when leave-me-alone (new.XYZ) then old.XYZ
> else new.XYZ
> end;
>
> And what about the where condition... hm, guess I am a bit confused.
>
IIUC, The NEW record is complete, with every value as it should be in the
newly saved tuple. There is no leave-me-alone concept. You don’t get to
know if the column was specified or not in the update command.
David J.
From | Date | Subject | |
---|---|---|---|
Next Message | Thiemo Kellner | 2023-11-10 15:41:46 | Re: Detection of which attributes should get set in update trigger |
Previous Message | Thiemo Kellner | 2023-11-10 09:46:05 | Detection of which attributes should get set in update trigger |