From: "Nekta Katz" <nekta_k@hotmail.com>
To: tgl@sss.pgh.pa.us
Cc: pgsql-sql@postgresql.org
Subject: Re: cast lo to oid
Date: Fri, 08 Nov 2002 11:24:12 +1100
Mime-Version: 1.0
Content-Type: text/plain; format=flowed
Message-ID: <F123QWBLYu7AHfo98xK00000a9a@hotmail.com>

I didn't realize there was a contrib/lo, I only created the lo type as 
described in the psqlodbc faq.

I have now installed the contrib/lo and everything is working fine.

I am using PG version 7.2

thanks.

>From: Tom Lane <tgl@sss.pgh.pa.us>
>To: "Nekta Katz" <nekta_k@hotmail.com>
>CC: pgsql-sql@postgresql.org
>Subject: Re: [SQL] cast lo to oid Date: Thu, 07 Nov 2002 10:16:21 -0500
>
>"Nekta Katz" <nekta_k@hotmail.com> writes:
> > I have the following table
>
> > create table scan_docs (
> >     docid   serial,
> >     shipno numeric(10),
> >     scan    lo,
> >     type text
> > );
>
> > when I try to create the following rule
>
> > create rule "delete_scan_docs_lo" as
> > on delete to "scan_docs"
> > do select lo_unlink (old.scan);
>
>Why aren't you using the trigger that type LO provides for this purpose?
>Seems rather pointless to use a nonstandard type and then ignore the
>primary (sole) feature it provides...
>
> > create rule "delete_scan_docs_lo" as
> > on delete to "scan_docs"
> > do select lo_unlink (old.scan::oid);
>
> > "psql:scan_docs_rule.sql:3: ERROR:  Cannot cast type 'lo' to 'oid' "
>
>Curious, as contrib/lo provides a function that's supposed to work
>for that:
>
>-- same function, named to allow it to be used as a type coercion, eg:
>--    CREATE TABLE a (image lo);
>--    SELECT image::oid FROM a;
>--
>CREATE FUNCTION oid(lo)
>RETURNS oid
>AS 'MODULE_PATHNAME', 'lo_oid'
>LANGUAGE 'C';
>
>What PG version are you using?
>
>			regards, tom lane
>
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