[blksv]

Actually, that's the whole point of RDBs: that you can alter your data model (in most cases) just by a simple DDL+DML query. And it is with NoSQL that you have to manually download all the affected data from the DB, run the transformation with consistency checks, and upload it back. Or, alternatively, you have to write your business logic so that it can work with/transform on-demand all the different versions of data objects, which to my taste is even more of a nightmarish scenario.