PL/SQL question

Started by Froggy / Froggy Corp.almost 22 years ago9 messagesgeneral
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#1Froggy / Froggy Corp.
froggy@froggycorp.com

Hello everyone,

I try to see if i can make a recursive function with a trigger set on
INSERT and doing an insert under my trigger function.

So i wrote a test function :

CREATE OR REPLACE FUNCTION testfunc() RETURNS SETOF RECORD AS '
DECLARE
use_t RECORD;
BEGIN

SELECT INTO use_t id_categorie FROM categorie ORDER BY id_categorie
DESC;
IF use_t.id_categorie<>50 THEN
INSERT INTO categorie (nom) VALUES (''test'');
END IF;

RETURN NULL;

END;
'LANGUAGE plpgsql;

The problem is that i can't exec this function to test it, psql return
the following error :

"ERROR: set-valued function called in context that cannot accept a set"

But my INSERT INTO works if i write it directly.

Someone get an idea ?

Thx in advance,
regards,

#2Stephan Szabo
sszabo@megazone23.bigpanda.com
In reply to: Froggy / Froggy Corp. (#1)
Re: PL/SQL question

On Tue, 20 Apr 2004, Froggy / Froggy Corp. wrote:

I try to see if i can make a recursive function with a trigger set on
INSERT and doing an insert under my trigger function.

So i wrote a test function :

CREATE OR REPLACE FUNCTION testfunc() RETURNS SETOF RECORD AS '
DECLARE
use_t RECORD;
BEGIN

SELECT INTO use_t id_categorie FROM categorie ORDER BY id_categorie
DESC;
IF use_t.id_categorie<>50 THEN
INSERT INTO categorie (nom) VALUES (''test'');
END IF;

RETURN NULL;

END;
'LANGUAGE plpgsql;

The problem is that i can't exec this function to test it, psql return
the following error :

"ERROR: set-valued function called in context that cannot accept a set"

Record set returning functions aren't called as:
select foo();
but instead as
select * from foo() AS foo(<columns>);

However, since you're not apparently actually returning a set of anything
in the function you may just want to change the return type.

#3Froggy / Froggy Corp.
froggy@froggycorp.com
In reply to: Froggy / Froggy Corp. (#1)
Re: PL/SQL question

Hello,

In fact the problem seems to come from the "INSERT INTO". I delete
everything from the function and only keep the "INSERT INTO" and get the
same problem.

Thx in advance for answers,
regards,

Stephan Szabo wrote:

Show quoted text

On Tue, 20 Apr 2004, Froggy / Froggy Corp. wrote:

I try to see if i can make a recursive function with a trigger set on
INSERT and doing an insert under my trigger function.

So i wrote a test function :

CREATE OR REPLACE FUNCTION testfunc() RETURNS SETOF RECORD AS '
DECLARE
use_t RECORD;
BEGIN

SELECT INTO use_t id_categorie FROM categorie ORDER BY id_categorie
DESC;
IF use_t.id_categorie<>50 THEN
INSERT INTO categorie (nom) VALUES (''test'');
END IF;

RETURN NULL;

END;
'LANGUAGE plpgsql;

The problem is that i can't exec this function to test it, psql return
the following error :

"ERROR: set-valued function called in context that cannot accept a set"

Record set returning functions aren't called as:
select foo();
but instead as
select * from foo() AS foo(<columns>);

However, since you're not apparently actually returning a set of anything
in the function you may just want to change the return type.

#4Stephan Szabo
sszabo@megazone23.bigpanda.com
In reply to: Froggy / Froggy Corp. (#3)
Re: PL/SQL question

On Wed, 21 Apr 2004, Froggy / Froggy Corp. wrote:

In fact the problem seems to come from the "INSERT INTO". I delete
everything from the function and only keep the "INSERT INTO" and get the
same problem.

A function like:
create function fz1() returns void as '
begin
INSERT INTO categorie (nom) VALUES (''test'');
RETURN;
end;' language 'plpgsql';

seems to work for me, what are you trying precisely?

#5Mike Nolan
nolan@gw.tssi.com
In reply to: Froggy / Froggy Corp. (#3)
Re: PL/SQL question

In fact the problem seems to come from the "INSERT INTO". I delete
everything from the function and only keep the "INSERT INTO" and get the
same problem.

Given that this is supposed to be a trigger function, what's
your 'create trigger' statement look like?

Part of the problem may be how your 'return null' is being handled,
and that can be related to when the trigger fires.
--
Mike Nolan

#6Jeff Eckermann
jeff_eckermann@yahoo.com
In reply to: Mike Nolan (#5)
Re: PL/SQL question
--- Mike Nolan <nolan@gw.tssi.com> wrote:

In fact the problem seems to come from the

"INSERT INTO". I delete

everything from the function and only keep the

"INSERT INTO" and get the

same problem.

Given that this is supposed to be a trigger
function, what's
your 'create trigger' statement look like?

Part of the problem may be how your 'return null' is
being handled,

AFAIK, returning null from a trigger function causes
the whole operation (insert, update or delete) to be
aborted, so the transaction is rolled back, including
the insert inside the function. You want to return
NEW instead.

and that can be related to when the trigger fires.
--
Mike Nolan

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#7Mike Nolan
nolan@gw.tssi.com
In reply to: Jeff Eckermann (#6)
Re: PL/SQL question

AFAIK, returning null from a trigger function causes
the whole operation (insert, update or delete) to be
aborted, so the transaction is rolled back, including
the insert inside the function. You want to return
NEW instead.

That's true on a 'before insert' trigger. An 'after insert' trigger
can return NULL because the insert that triggered it has already
taken place and the value returned by the trigger function is ignored.

That's why it was important to ask the original poster what kind of
trigger it was 'before insert' or 'after insert'.
--
Mike Nolan

#8Froggy / Froggy Corp.
froggy@froggycorp.com
In reply to: Jeff Eckermann (#6)
Re: PL/SQL question

I allways get the same error :

ERROR: set-valued function called in context that cannot accept a set

It seems to not accept the "(''test'')". Maybe i made a mistake by
adding the plpgsql langage, but i follow the documentation about that.

If i try to change the insert by "INSERT INTO categorie (id_categorie)
VALUES (''test'');" i got an error msg that "test" is not an integer.
(id_categorie is the primary key of the table).

thx in advance,
regards,

Jeff Eckermann wrote:

Show quoted text
--- Mike Nolan <nolan@gw.tssi.com> wrote:

In fact the problem seems to come from the

"INSERT INTO". I delete

everything from the function and only keep the

"INSERT INTO" and get the

same problem.

Given that this is supposed to be a trigger
function, what's
your 'create trigger' statement look like?

Part of the problem may be how your 'return null' is
being handled,

AFAIK, returning null from a trigger function causes
the whole operation (insert, update or delete) to be
aborted, so the transaction is rolled back, including
the insert inside the function. You want to return
NEW instead.

and that can be related to when the trigger fires.
--
Mike Nolan

---------------------------(end of
broadcast)---------------------------
TIP 8: explain analyze is your friend

__________________________________
Do you Yahoo!?
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#9Rory Campbell-Lange
rory@campbell-lange.net
In reply to: Froggy / Froggy Corp. (#8)
Re: PL/SQL question

The function should be called as "select * from function_name (xyz)"
rather than "select from function_name (xyz)", I would guess.

Rory

On 21/04/04, Froggy / Froggy Corp. (froggy@froggycorp.com) wrote:

I allways get the same error :

ERROR: set-valued function called in context that cannot accept a set

--
Rory Campbell-Lange
<rory@campbell-lange.net>
<www.campbell-lange.net>