Re: RULES on SELECT with JDBC/perlDBI from other RDBMS

On 10/6/05 9:07 PM, "Bath, David" <dave(dot)bath(at)unix(dot)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