Обсуждение: Triggers

Hello, I have this doubt since I started using PostgreSQL, a few months ago.

Why triggers are defined that way? I mean, in others DBMS you simply write:

CREATE TRIGGER <trigger_name> ... bla bla bla
BEGIN
  ....
END;

Why you should write a function first and then the trigger, which must call that function?

What are the advantages/disadvantages of that? Where can I find more information?

--
Germán Hüttemann Arza

> Why you should write a function first and then the trigger, which must
> call that function?
>
> What are the advantages/disadvantages of that? Where can I find more
> information?

The PG way seems very natural to me:
you can write functions that do something and then have many triggers
call that same function.

Also there's not just PL/PGSQL: you might want
to define a function in C or Perl and then have a trigger call it.

Bye, Chris.


--

Chris Mair
http://www.1006.org

Chris Mair <chrisnospam@1006.org> writes:
>> Why you should write a function first and then the trigger, which must
>> call that function?

> ... there's not just PL/PGSQL: you might want
> to define a function in C or Perl and then have a trigger call it.

Right, that's the real reason: this approach doesn't constrain which
PL you can write your triggers in.

            regards, tom lane