Re: Trigger questions

On Thu, May 4, 2023 at 7:04 AM Justin <zzzzz(dot)graf(at)gmail(dot)com> wrote:

>
>
> On Thu, May 4, 2023 at 9:49 AM DAVID ROTH <adaptron(at)comcast(dot)net> wrote:
>
>> 1) Can I create a trigger on a view?
>> 2) Do triggers cascade?
>>
>> Say I have an insert trigger on a table.
>> And, I have an insert trigger on a view that references this table
>> If I do an insert on the view, will both triggers fire?
>>
>
> Can not have triggers on Views, Views use RULES which are DO INSTEAD.
> https://www.postgresql.org/docs/current/rules.html
>

Our users need not care or even know about this particular implementation
detail of views. For them, views are a fundamental concept.

The description of create trigger makes is perfectly clear that views are a
valid "table-like" target for a trigger.

> CREATE TRIGGER creates a new trigger. CREATE OR REPLACE TRIGGER will
either create a new trigger, or replace an existing trigger. The trigger
will be associated with the specified table, view, or foreign table and
will execute the specified function function_name when certain operations
are performed on that table.

https://www.postgresql.org/docs/current/sql-createtrigger.html

Depending on the view definition, the need for a trigger may be removed
since some views are auto-updatable.

David J.