What's the attraction of schemaless database systems?
I've been hearing a lot of talk about schema-less (often distributed) database systems like MongoDB, CouchDB, SimpleDB, etc... While I can understand they might be valuable for some purposes, in most of my applications I'm trying to persist objects that have a specific number of fields of a specific type, and I just automatically think in the relational model. I'm always thinking in terms of rows with unique integer ids, null/not null fields, SQL datatypes, and select queries to find sets. While I'm attracted to the distributed nature and easy JSON/RESTful interfaces of these new systems, I