Re: Trigger function to know which fields are being updated

--- Bernard Cheung <cheungsw(at)hotmail(dot)com> wrote:
> I am writing a trigger function. How can I know
> which fields are being
> updated in the PL/SQL function?
>
> For example I have a table here:
>
>
> CREATE TABLE COMPANY (
> COMPANY_ID VARCHAR(10) NOT NULL,
> NAME VARCHAR(30),
> ADDRESS VARCHAR(30));
>
> I want to write a trigger to block all update
> statements without updating
> NAME. I tried the following code block and it
> doesn't work:
>
>
> IF TG_OP = ''UPDATE'' THEN
> IF NEW.NAME IS NULL THEN
> RAISE NOTICE ''Field NAME must be
> provided!'';
> END IF;
> END IF;

That should work. Perhaps "name" is not actually
null, but rather an empty string? In that case, your
test needs to be: "IF NEW.NAME IS NULL OR NEW.NAME =
'''' THEN..."

>
> Are there any functions like the Oracle's UPDATING()
> predicate?
>
> Bernard Cheung
>
>
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