Recursive update

Hi,

I'm doing some PL/pgSQL programming at work and today I realized a small
glitch in my application design.

The following recreates my problem...

I have two tables with triggers on each:

    CREATE TABLE "public"."tableone" (
      "id" SERIAL,
      "columnone" VARCHAR(64),
      "columntwo" VARCHAR(64),
      "checkfield" BOOLEAN,
      CONSTRAINT "tableone_pkey" PRIMARY KEY("id")
    ) WITH OIDS;

    CREATE TRIGGER "tableone_update" BEFORE UPDATE
    ON "public"."tableone" FOR EACH ROW
    EXECUTE PROCEDURE "public"."tableone_update"();

    CREATE TABLE "public"."tabletwo" (
      "id" SERIAL,
      "name" VARCHAR(64),
      CONSTRAINT "tabletwo_pkey" PRIMARY KEY("id")
    ) WITH OIDS;

    CREATE TRIGGER "tabletwo_insert" BEFORE INSERT
    ON "public"."tabletwo" FOR EACH ROW
    EXECUTE PROCEDURE "public"."tabletwo_insert"();

Then I have the trigger functions:

    CREATE OR REPLACE FUNCTION "public"."tableone_update" () RETURNS
trigger AS'
    begin

         if ((new.columntwo!=old.columntwo) OR (old.columntwo is null AND
new.columntwo is not null)) then
            return new;
         end if;

         -- Call the "insert function".
         insert into tabletwo (name) values (''inserted by function
insert_into_tabletwo'');
         return new;
    end;
    'LANGUAGE 'plpgsql' IMMUTABLE CALLED ON NULL INPUT SECURITY INVOKER;

    CREATE OR REPLACE FUNCTION "public"."tabletwo_insert" () RETURNS
trigger AS'
    begin

       if exists (select * from tableone where (checkfield=false OR
checkfield is null) and id=1) then
         update tableone set columntwo=''updated by insert in
tabletwo'',checkfield=true WHERE id=1;
       end if;

      return new;
    end;
    'LANGUAGE 'plpgsql' IMMUTABLE CALLED ON NULL INPUT SECURITY INVOKER;

Now I do the following:
    INSERT INTO tableone (id,columnone, columntwo,checkfield) VALUES
(1,'from initial insert','from initial insert',false);
    UPDATE tableone set columnone='updated by me' WHERE id=1;

The content of tableone is then:
  id | columnone           | columntwo                     | checkfield
----+---------------------+-------------------------------+------------
   1 | from initial insert | updated by insert in tabletwo | true


I believe I'm having the same issue as in this thread:

http://groups-beta.google.com/group/comp.databases.postgresql.general/browse_thread/thread/5ead4260393ecd57/37c8b4a1b7562221?q=recursive+update+postgresql&_done=%2Fgroups%3Fq%3Drecursive+update+postgresql%26hl%3Den%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DN%26tab%3Dwg%26&_doneTitle=Back+to+Search&&d#37c8b4a1b7562221

I'm trying to do an update on a table which results in another
subsequent update of the same table. Only the second (subsequent) is
actually executed on the table. I'm not sure I understand why this is
not allowed, because I can see many cases where recursive updates would
be a very nice thing to have available.

Is this maybe a thing which should be raised for the PostgreSQL
developer team?

Thanks in advance and happy new year!

--
Thomas Braad Toft