Re: [SQL] cast lo to oid

[Nekta Katz]

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 <[EMAIL PROTECTED]>
To: "Nekta Katz" <[EMAIL PROTECTED]>
CC: [EMAIL PROTECTED]
Subject: Re: [SQL] cast lo to oid Date: Thu, 07 Nov 2002 10:16:21 -0500

"Nekta Katz" <[EMAIL PROTECTED]> 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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