The SQL database (a brilliant, wonderful thing despite the hatred it gets) is an example. When you write a query, you don't tell it which indexes to hit and how

The SQL database (a brilliant, wonderful thing despite the hatred it gets) is an example. When you write a query, you don't tell it which indexes to hit and how to micromanage details. You send a declarative query to this "black box" that, most of the time, does the right thing. That sounds very much to me like 'A SQL database is an abstraction', and very little like 'A SQL database is somehow related to OO'. In facts it's really unnatural to map objects to relations, which is why you need yet another ORM abstraction on top of it, just to satisfy the OO silver bullet.