From: Rod Taylor <rbt@rbt.ca>
To: Stefano Vita Finzi <stefano.vita@pronesis.it>
Cc: pgsql-sql@postgresql.org
Subject: Re: plpgsql recursion
Date: 22 May 2003 21:59:43 -0400
Message-ID: <1053655182.279.28.camel@jester> (raw)
In-Reply-To: <01a601c31ef0$4a628220$0600a8c0@stefano>
References: <01a601c31ef0$4a628220$0600a8c0@stefano>
> IF t_rec.node = testing THEN
> RETURN ''Circular'';
> ELSE
> PERFORM dba_test(t_rec.node,testing);
> END IF;
> I would use this function BEFORE inserting the new row. But if i try SELECT
> dba_test(4,1); i don't have the result i expect. Can i you give me an hint
> where am i wrong?
It's probably working as it's written :) Once it finds 'Curcular' and
returns it to the recursed call of dba_test, you immediately throw away
the return value.
PERFORM should probably be replaced with:
ELSE
-- ret is a variable
SELECT dba_test(t_rec.node, testing) INTO ret;
IF ret = ''Circular'' THEN
RETURN ret;
END IF;
END IF;
More to the point, if you're attempting to prevent circular items, and
this function will be used in the form of a trigger, then simply RAISE
EXCEPTION. This way you can ignore having to deal with returned values.
--
Rod Taylor <rbt@rbt.ca>
PGP Key: http://www.rbt.ca/rbtpub.ascAttachments:
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To: pgsql-sql@postgresql.org
Cc: rbt@rbt.ca, stefano.vita@pronesis.it
Subject: Re: plpgsql recursion
In-Reply-To: <1053655182.279.28.camel@jester>
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