Re: Data Migration Methodologies -- FoxPro to Access

On Thu, 22 Aug 2002 09:34:20 -0400, "Koronis Rift" <foo_at_bar.com> wrote:
>Am just beginning to undertake a rather large[1] data migration/data
>conversion project, moving from an off-the-shelf customer information system
>to a custom-built one. Current system uses Visual FoxPro (appx. 230 tables),
>new system uses Access 97 (appx. 80 tables).
>
>[1] Well, not huge databases -- but large in the sense that it's just myself
>and a contractor working on the migration.

The *new* system is using something as retro as Access *97*? Yikes.

>The Problem: New database was designed "from scratch", solely from the
>enterprise data model. The existing database schema was not evaluated at all
>for the purposes of migrating the legacy data to the new system. Thus, my
>question.

Yes, in such situations, questions are common! See Paul Vernon's message, no doubt there will be many changes necessary to the new desk-built schema.

>I am looking for the following:
>1. General info on data migration methodology (comp.databases.theory)
>2. Tips specific to FoxPro/Access regarding the mechanics of migration
>(microsoft.public.access.conversion)
>
>What I have found already:
>- "The Complete Data Migration Methodology", Joseph Hudicka
>- "The Five Legacy Data Contaminants You Will Encounter In Your Warehouse
>Migration", Vality Technology, Inc.
>- "Avoid Data Migraines During Data Migration", Christine Raker and Robert
>Knowlton
>
>Any tips, links, articles, white papers, jokes, war stories, etc... would be
>greatly appreciated! (No need to crosspost replies, I'll track the thread in
>both newsgroups)

Well, you may be over-researching things, though as someone who's done several data migrations, I'd be interested in seeing these books, I'm not familiar with any of them.

Here's a few of my own favorite tips and techniques:

• LOOK at the data, dump large wads of it onto paper, browse more on the screen. Lots of legacy databases misuse fields, and if you try to do conversion based on what they're *supposed* to contain, it won't work. Call this "database hygiene".
• Practice, practice, practice: once you have the mechanics worked out, do several trial conversions. When the day comes to do it live, hopefully you just push the button, go to lunch, and come back with the cleanest possible conversion -- and a list of exceptions.
• You often want to clean up the data during conversion. Don't ever believe it's really a conversion, there are always wishlist items for maintenance and others for enhancement. There will likely be a fair amount of semi-manual effort involved. Be ready to write lots of action queries to fix up the data during conversion.

Good luck!

Joshua Stern Received on Fri Aug 23 2002 - 21:44:13 CEST