Re: Migration to Oracle

From: DA Morgan <damorgan_at_psoug.org>
Date: Mon, 03 Mar 2008 08:55:32 -0800
Message-ID: <1204563332.387545@bubbleator.drizzle.com>


Serge Rielau wrote:
> If SQL Developer raises a NULL pointer exception, have you tried to get
> behind that problem?
> Anyway, there are other tools you can try. E.g. SwisSQL which converts
> from anywhere to anywhere. Naturally I cannot vouch for their quality
> going from SQL Server to Oracle...
> http://www.swissql.com/
>
> I think the disconnect between you and Daniel is that Daniel considers
> redesign on migration a must, while your bosses consider it a must not.
> Your bosses win that argument (for now) s they hold the purse string ;-)
>
> Just be advised that in any automated migration the end result is an
> emulation. That is you will be running SQL Server on Oracle with the
> obvious loss of performance along the way. After your functional
> migration you will have to selectively redesign anything that is
> performance critical.
>
> Cheers
> Serge

Serge is correct in that I consider a redesign essential. Every time I see someone try to do this on the cheap ... they fail ... and end up spending more time and more money.

SQL Server's underlying architecture will corrupt data in Oracle just as Oracle's underlying architecture will corrupt SQL Server. Try to do a brain-dead migration and you will just make a predicable mess.

Dump the data and reload it. Recode the TSQL to PL/SQL.

Consider, just for a moment, the implications of moving from an environment without MVCC, without sequences, without BEFORE triggers, without array processing, without undo, without flashback, etc. And you want to move that code into Oracle. It isn't going to happen except in a fantasy.

-- 
Daniel A. Morgan
Oracle Ace Director & Instructor
University of Washington
damorgan_at_x.washington.edu (replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org
Received on Mon Mar 03 2008 - 10:55:32 CST

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