c0d3lib@[EMAIL PROTECTED]
wrote:
> On Apr 24, 5:42 pm, Karl Hanson <kchan...@[EMAIL PROTECTED]
> wrote:
>> c0d3...@[EMAIL PROTECTED]
wrote:
>>
>> <snip>
>>
>>
>>
>>> Thanks for the reply, Larry. Yes, The scenario you described is
>>> what I'm trying to achieve. The tables will reside on the DB/2 for
>>> Linux host, and need to be accessible to the iSeries RPG/CL
>>> programs. As for your question about migrating the code, this
>>> would play into a larger strategy that allows us to migrate some of
>>> the more interesting processes of a legacy iSeries application.
>>> The application is way too large to try migrating the entire thing.
>>
>>> Have you ever tried or seen a similar implementation using the
>>> iSeries as a client to any non-iSeries system? Do you know of any
>>> issues I should be expecting, such as the differences in security
>>> implementations, etc? Performance is already a concern, but all I
>>> can do there is measure the differences once I have at least a basic
>>> configuration established.
>>
>> DDM provides a different level of function than DRDA. DDM allows
>> fairly
>> transparent trans****t of "file I/O" requests from the System i
>> running
>> the RPG application, to a remote System i (for example) that can
>> perform
>> these file I/O requests. The RPG program will typically do I/O
>> requests
>> such as read by key (SETLL?), read next key equal, read by relative
>> record no., etc. As Larry mentioned, these are not SQL operations and
>> DB2 for LUW does not sup****t "files", nor this type of file I/O
>> (because
>> it is not, and does not map to,
>>
SQL).http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic...
>>
>> DRDA on the other hand allows trans****t of SQL requests between
>> systems. But since your RPG programs do file I/O and not SQL, DRDA
>> would not
>> sup****t your proposal. In other words, there is no function to
>> automatically convert file I/O requests to SQL requests, as part of
>> either DDM or DRDA. As you correctly surmised, in order to use DRDA
>> (SQL), the RPG file I/O would need to be appropriately replaced with
>> embedded SQL, or the
>>
equivalent.http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic...
>>
>> If the business logic to maintain the data currently resides on
>> System
>> i, what is the motivation to move the data to DB2 on Linux? If Linux
>> access to data on System i is the goal, could facilities like ODBC or
>> JDBC (ie on a Linux client) provide that, w/o migrating the data?
>>
>> --
>> Karl Hanson
>
> The business logic is being migrated in pieces, so not all of it will
> reside on the iSeries, but inevitably there will be non-migrated
> processes that will still require access to the same files.
>
> My misunderstanding of DRDA and DDM is that I thought DDM was a subset
> of DRDA. I was under the impression, any operation a program could
> perform using DDM would translate to some function in DRDA and hence
> to SQL concepts. Thanks for clearing that up for me.
Disclaimer:
I have no experience with iSeries, AS/400, RPG etc.
That being said, a quick Google-search for "db2+migration+rpg+linux" gave
a
number of promising hits, for instance these 2 links for a company called
PKS:
http://www.pks.de/products/iSeries/migration_tools_400.htm
http://www.pks.com/english/aktuelles/pdf_dateien/2008/PKS%20MM%20JAN08%20E.pdf
HTH
--
Jeroen
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