I totally agree with this. Interesting point about NoSQL! I'm not sure if it's just the query language though - the definition language needs to make creating

I totally agree with this. Interesting point about NoSQL! I'm not sure if it's just the query language though - the definition language needs to make creating columns that are sum types trivial. For one-to-many data this might be a slight generalization of foreign key (compound of table tag + foreign key for that table). This can work for one-to-one data too, but can be a bit annoying having lots of tables compared to doing adding a couple nullable columns (plus there's also data locality differences). I suppose a wrapper language that covers both DDL and DML could work.