Message-ID: <3ED47B6E.6010209@ualg.pt>
Date: Wed, 28 May 2003 10:03:42 +0100
From: Luis Sousa <llsousa@ualg.pt>
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To: Stefano Vita Finzi <stefano.vita@pronesis.it>
Cc: pgsql-sql@postgresql.org
Subject: Re: plpgsql recursion
References: <01a601c31ef0$4a628220$0600a8c0@stefano>
In-Reply-To: <01a601c31ef0$4a628220$0600a8c0@stefano>
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Can you post the recursion function that you use on this case to get out 
the information from the table ?

Thanks,
Luis Sousa

Stefano Vita Finzi wrote:

>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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