From: David Heinemeier Hansson Date: 2005-10-28T04:15:44+09:00 Subject: Re: Ruby on Rails version of osCommerce in PHP? > Ah ... but at that point, in many ways, he's wrong. The moment you have > data to migrate, there's a second program working on the database. > Unless -- as appears to be the case with Rails at this point -- your > migration is done using the exact same database access layer as your > primary application, you will get garbage data at some point. To quote from the article (especially the "my opinions are confined to dealing with application databases"): "Before the DBA-induced side of your brain explodes at that statement, please do read Martin Fowler's article on the difference between application and integration databases. And realize that my opinions are confined to dealing with application databases (and that doing integration through the database belongs in a time where Beverly Hills 90210 was a hit show on TV). Hopefully that calmed you down again." But it was my fault. I should have decorated that caveat with underline, bold, and possibly blink. So actually we're very much in agreement. My strong opinions on this matter are strongly scoped. What we might agree on is whether that scope is a desireable one or not. And to further the group hug, I'm pretty neutral about foreign key constraints. It's triggers, business constraints ("don't insert if balance > 100"), and stored procedures that deserve the "Evil" label. -- David Heinemeier Hansson http://www.loudthinking.com -- Broadcasting Brain http://www.basecamphq.com -- Online project management http://www.backpackit.com -- Personal information manager http://www.rubyonrails.com -- Web-application framework