Re: DDM and SQL

["Alexei Pytel" <pytel@xxxxxxxxxx>]

SQL used DRDA for ages for access to remote databases.
DB2 Multisystem was introduced, if I remember correctly, in V3R2/V3r7
timeframe, and it allows to split an SQL table between separate machines
and still treat it as a single table.
DB2 Multisystem also uses DRDA for communication.
You may think about DRDA as a specialized communication protocol.

    Alexei Pytel
always speaking for myself




                      "Mark Waterbury"
                      <mark.s.waterbury@worldn        To:       
<midrange-l@midrange.com>
                      et.att.net>                     cc:
                      Sent by:                        Subject:  Re: DDM and SQL
                      midrange-l-admin@midrang
                      e.com


                      10/09/2002 05:45 PM
                      Please respond to
                      midrange-l





Hi, Vern:

I think that DRDA might be part of the architecture; I think on
newer OS/400 releases, it is called "DB2 Multisystem" -- all I know
is, in ISQL (aka. STRSQL), it "all just works!"... (assuming the
other machine is configured on the network, etc., and has been
given a "Database name"... e.g. ADDRDBDIRE, WRKRDBDIRE)

Mark

----- Original Message -----
From: "Vernon Hamberg" <vhamberg@attbi.com>
To: <midrange-l@midrange.com>
Sent: Wednesday, October 09, 2002 4:40 PM
Subject: RE: DDM and SQL


> Kirk
>
> Are you thinking of DRDA? That's how SQL gets to another system. I
believe
> the statement is sent to the other system (probably in a DDM session) and
> then the work happens remotely, with only the result passed back. Terms
> like RUW and DUW (remote and distributed unti of work, resp.) are used
> here, so I suspect the work is at the other end. Hope so, anyway.
>
> Vern
>
> At 04:28 PM 10/9/02 -0600, you wrote:
> >Kirk,
> >         When I use STRSQL or RUNQRY over a DDM file I get the message,
> >"QRY1609 - File PCRPACHR in PCRDDMFILE is not a data base file, cannot
> >query." Or "SQL7001 - File PCRPACHR in PCRDDMFILE not database file."
> >
> >
> >Thank you,
> >Matt Tyler
> >Mattt@wincofoods.com
> >
> >-----Original Message-----
> >From: Kirk Goins [mailto:kirkg@pacinfosys.com]
> >Sent: Wednesday, October 09, 2002 16:22
> >To: Midrange-L (E-mail)
> >Subject: DDM and SQL
> >
> >OK you database and DDM Gurus...
> >
> >I'm not looking for a why or why not to do this, I'm looking for HOW it
does
> >it..
> >
> >Let's assume on a local machine I use SQL to select say 5,000 records
from
> >say a 100,000 record file and assuming that the query optimizer uses a
seq
> >read to get those 5,000 records... there is lots of I/O
> >
> >Now Let's move the data to a remote system and use DDM. Does the machine
> >with the ACTUAL DATA do all the work and only return the 5,000 records
> >across the link or does EVERY Record get passed via DDM the source
machine
> >which throws out the unwanted?
>
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