It very much depends. I've seen too many cases when business logic was moved to the database layer, with absolutely disastrous effects. Scaling application back

It very much depends. I've seen too many cases when business logic was moved to the database layer, with absolutely disastrous effects. Scaling application backends doing map-reduce on a pre-filtered datasets is way easier than scaling database to handle five-way joins. Yet,I've seen opposing cases too, when rdbms was used as a huge key-value storage , and was pushing hundreds of thousands of rows to tens of backends, sucking it's bandwidth dry.