Rails 3: DataMapper instead of ActiveRecord

After all the hussle about Rails 3, can I, after all, painlessly use开发者_如何学编程 DataMapper without almost changing my ActiveRecord code so that I could run my Rails at GAE without any bother?

Well, you still have to add the properties for DataMapper, and a bunch of code in the gems you are using might not be ORM-agnostic. And you have to change your queries to the DM syntax (which is IMO more beautiful than the AR one), or you can use some of the old AR ones by using the gem dm-ar-finders. And what's GAE?