Re: Returning NEW in an on-delete trigger

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От Jeff Davis
Тема Re: Returning NEW in an on-delete trigger
Дата
Msg-id 1221764432.6194.254.camel@dell.linuxdev.us.dell.com
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Ответ на Returning NEW in an on-delete trigger  ("Michael Nolan" <htfoot@gmail.com>)
Список pgsql-general
On Thu, 2008-09-18 at 14:21 -0400, Michael Nolan wrote:
> Recently I discovered a coding error of mine in a trigger that is
> called only for deletes.
>
> I was returning NEW instead of OLD.
>
> Since NEW is undefined when deleting a row, it was failing and the row
> wasn't being deleted.

In PL/pgSQL, NEW is NULL for BEFORE DELETE triggers. It doesn't appear
to be obviously documented that this is the case (which is, I assume,
why you said it is undefined), and I agree that it can cause confusion.

> However, it was failing silently.  Shouldn't this have recorded an
> error or warning somewhere?

This is a feature, not a bug. Sometimes you don't want to delete a
record, and returning NULL is the way to do that.

Regards,
    Jeff Davis


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