From: =?iso-8859-2?B?TOFzemzzIFRpYm9y?= <ltibor@mail.tiszanet.hu>
To: "pgsql-odbc" <pgsql-odbc@postgresql.org>
Subject: RE: [INTERFACES] 7.1 beta 3 Linux ODBC BEGIN Behaviour 
Date: Sat, 10 Feb 2001 19:15:56 +0100
Message-ID: <NEBBJDDFALKDHFBLCGCPIEBFCAAA.ltibor@mail.tiszanet.hu>
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> It'd be nice if ODBC could distinguish SELECT FOR UPDATE from plain
> SELECT, but in practice it cannot reliably do so.  Doubtless we could
> extend ODBC to look for "FOR UPDATE" in the text of the query, but
> that will only catch simple situations.  Consider these possibilities:
> 
> * A view or rule invoked by the query uses FOR UPDATE.  (Pre-7.1, we
> didn't support FOR UPDATE in views ... but we do now.)
> 
> * A function invoked by the query does SELECT FOR UPDATE internally.
> 
> For that matter, it's quite possible for a function invoked by a SELECT
> to do INSERT/UPDATE/DELETE internally.  Therefore, it's impossible for
> the ODBC driver to reliably distinguish a pure SELECT from a SELECT that
> causes locking or even data updates.
> 
> Given these considerations, I think it's a mistake for ODBC to treat
> SELECT differently from other queries for the purpose of setting
> transaction boundaries.
> 
> 			regards, tom lane

Thank you Tom. I agree. Regards, Tibor

Tibor Laszlo
ltibor@mail.tiszanet.hu