From: Stefano Vita Finzi <stefano.vita@pronesis.it>
To: pgsql-sql@postgresql.org
Subject: plpgsql recursion
Date: Tue, 20 May 2003 18:53:08 +0200
Message-ID: <01a601c31ef0$4a628220$0600a8c0@stefano> (raw)
Greetings!
I have a table like:
node parent
1 2
2 3
3 4
Since i traverse this table with a recursive function, i want to avoid
infinite recursion loop. I have wrote a function to check that a new record
does not create a circular dependency. The function i wrote is as follow:
CREATE OR REPLACE FUNCTION dba_test(INTEGER,INTEGER) RETURNS TEXT AS '
DECLARE
traversing ALIAS FOR $1;
testing ALIAS FOR $2;
t_rec RECORD;
BEGIN
FOR t_rec IN SELECT node,parent FROM dba_test WHERE parent = traversing
LOOP
IF t_rec.node = testing THEN
RETURN ''Circular'';
ELSE
PERFORM dba_test(t_rec.node,testing);
END IF;
END LOOP;
RETURN ''ok'' || testing::text;
END;
' LANGUAGE 'plpgsql';
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?
Thank you!
Stefano Vita Finzi
kluge@despammed.com
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To: pgsql-sql@postgresql.org
Cc: stefano.vita@pronesis.it
Subject: Re: plpgsql recursion
In-Reply-To: <01a601c31ef0$4a628220$0600a8c0@stefano>
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