From: CG <cgg007@yahoo.com>
To: pgsql-sql@postgresql.org
Subject: DROP IF ...
Date: Tue, 24 May 2005 10:44:54 -0700 (PDT)
Message-ID: <20050524174454.67174.qmail@web32501.mail.mud.yahoo.com> (raw)
PostgreSQL 7.4 ...
I'm trying to find a way to drop a table via SQL if it contains 0 rows. Here
was my thought:
CREATE OR REPLACE FUNCTION dropif(text, bool)
RETURNS bool AS
'DECLARE
tblname ALIAS FOR $1;
condition ALIAS FOR $2;
BEGIN
IF (condition) THEN
EXECUTE(\'DROP TABLE "\' || tblname || \'";\');
END IF;
RETURN \'t\'::bool;
END;'
LANGUAGE 'plpgsql' VOLATILE;
... then ...
BEGIN;
CREATE TABLE testtbl (i int4);
SELECT dropif('testtbl',(SELECT count(*)::int4 FROM testtbl) = 0);
ERROR: relation 286000108 is still open
CONTEXT: PL/pgSQL function "dropif" line 6 at execute statement
... It makes sense. The select is still open when the table is going to be
dropped. I need a different strategy.
Please advise!
CG
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To: pgsql-sql@postgresql.org
Cc: cgg007@yahoo.com
Subject: Re: DROP IF ...
In-Reply-To: <20050524174454.67174.qmail@web32501.mail.mud.yahoo.com>
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