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Re: PQftype() and Oid

From: Andro <andromede(at)gmail(dot)com>
To: pgsql-interfaces(at)postgresql(dot)org
Subject: Re: PQftype() and Oid
Date: 2006-08-07 07:34:34
Message-ID: da7021e0608070034w5b40b060qf7c7b8b9094b9afa@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-interfaces
While I agree this is a reliable way of matching, this has a
significant impact on performance to make an extra query on each field
that I want the type of ! And this makes this approach definitly not
the one to implement IMO.

Best,

Charles

On 8/5/06, Volkan YAZICI <yazicivo(at)ttnet(dot)net(dot)tr> wrote:
> On Aug 04 04:38, Andro wrote:
> > Oids are in pg_type catalog (server side) and src/include/catalog/pg_type.h
> > (hard-wired).
> >
> > But what should we compare the Oid returned by PQftype() with?
> > Let's say I want to check if column 1 is a VARCHAR, do I have to
> >
> > if (PQftype(res,1) == 1043)
> > ...;
> >
> > ?
> > Isn't there a kind of enum which we could rely on to find out types? What if
> > Oids change in pg_type.h?
>
> You can make another query on pg_type to learn OID of a specific type.
> And then compare it with the returned one from PQftype(main_query_res).
>
> Furthermore, I think this is the only reliable way of accomplising this
> task. (IIRC, PHP PostgreSQL API does same too.) Otherwise, when you use
> hard-wired headers (e.g. by including pg_type.h) what will you do when
> related server has a custom type that isn't get shippied with the
> PostgreSQL headers you included.
>
>
> Regards.
>

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