The interview is from July 2009. I think Rails already had its ORM then. DHH says:

"The model part in an MVC application is where all the business logic is kept. Those are all the classes like ‘Post’ and ‘Category’ and ‘Author’ and all those things –say if you're making a weblog– you'd keep all that stuff in the Model. And you'd have all the logic about whether the author is allowed to make a post and how the relationship between posts and comments work together. Those are all sitting in the model, so that's all the business logic, very often backed by a database in some sense, not always, but most of the time. And that's where in Rails we're using something called ‘ActiveRecord’. Which is this way of mapping database tables to objects, and then decorating those objects with logic."