User-Agent: Microsoft-Entourage/10.1.4.030702.0
Date: Fri, 07 Oct 2005 06:23:53 -0400
Subject: Re: RULES on SELECT with JDBC/perlDBI from other RDBMS
From: Sean Davis <sdavis2@mail.nih.gov>
To: <dave.bath@unix.net>, <pgsql-sql@postgresql.org>
Message-ID: <BF6BC4F9.1006C%sdavis2@mail.nih.gov>
In-Reply-To: <200510071107.38564.dave.bath@unix.net>
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On 10/6/05 9:07 PM, "Bath, David" <dave.bath@unix.net> wrote:

> Folks,
> 
> I'm looking at using pg to be the main platform for integrating info
> from other RDBMS products (particularly Oracle) as pg seems to be
> the most flexible RDBMS around.
> 
> Disregarding writing to foreign products, query-plan efficiencies,
> or differences of SQL dialect, I'd like to have a way of setting
> up a fairly-transparent SELECT within pg that pulls rows from the
> other product.  I wonder if anyone has attempted something like
> this, and can recommend (or even deprecate) an approach, and perhaps
> point to a code template.
> 
> Possible approaches that occur to me include
> 1. For the low-level integration ....
>  a) Use of "foreign" JDBC thin client within PL/Java
>  b) Use of untrusted perl DBI/DBD
>  c) Use of low-level C code (e.g. declaring Oracle OCI calls
>     to pg) - very labor intensive
> 2. For "transparent" use by other routines....
>  Create pg table/view, then write rules that use functions
>  returning rows (including barf exceptions if someone tries
>  writing to a table).
> 
> If I can embed a java thin client binary/jar for the foreign
> database in pg and use it using pg pl/java, then I'd like to
> go that path as it would decrease setup/admin effort when
> porting to other platforms, as there would be few dependencies
> on things like external perl modules.
> 
> If any pg developer gurus are reading this, perhaps such templates
> might be worthwhile including in the contrib bundle?
>  

The DBI-link project is quite useful for doing just what you describe, if I
understand you correctly.

http://pgfoundry.org/projects/dbi-link/
http://www.pervasivepostgres.com/postgresql/tidbits_June05.asp

Sean