Trigger Documentation - Mailing list pgsql-docs

From al_nunes@ciclotecnologia.com.br
Subject Trigger Documentation
Date
Msg-id Pine.LNX.4.21.0106081145560.8814-100000@pinguim.ciclotecnologia.com.br
Whole thread Raw
Responses Re: Trigger Documentation  (hubert depesz lubaczewski <depesz@depesz.pl>)
List pgsql-docs
Hi,

I could not find enough examples about the usage of triggers with
PostgreSQL. Searching in the list files, I found out that there are some
examples in contrib/spi/ directory, but this examples scared me a little
because all the triggers are written in C.

What I need to do now is very simple, I want to make a trigger that check
if some text field is null. If it is, I want to record something on
it. What I was trying (unsuccessfully):

CREATE FUNCTION ins_ip() RETURNS OPAQUE AS '
BEGIN
 IF NEW.<field> ISNULL THEN
  NEW.<field> := "something";
   RETURN NEW;
END;
' LANGUAGE 'plpgsql';


CREATE TRIGGER tr_ponto_ins BEFORE INSERT OR UPDATE ON ponto
    FOR EACH ROW EXECUTE PROCEDURE ins_ip();


Ie tryed to put something beetwen quotes, double-quotes, nothing
worked. Will I have to write an enormous trigger in C?

Regards,

Alvaro Nunes Melo



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