Comment by pjungwir

I like a SQL a lot, but I wouldn't mind a nicer interface to a relational database. TutorialD seems more elegant and expressive than EdgeQL though. If I were designing a new query language, that's where I would look for inspiration. Anyway I'm glad to see people experimenting!

I am waiting for someone to write a paper titled "SQL NULL is (nearly) a Monad." It is "contagious" just like mapping over None. Sometimes I think it'd be cool to add Maybe<T> columns to Postgres, where operators would do the right thing for Some(x) vs None, but then I think, "Wait, that's how it already works!" At least it is very close. But one way or another I would love to see a re-assessment of SQL NULL from the perspective of category theory. If we could redo NULLs as Maybe types, what would that improve? Incidentally, Leonid Lybkin published a really cool paper in 2014 about handling NULLs with category-theory ideas, but it is more about drawing inferences from incomplete premises ("Incomplete data: what went wrong and how to fix it"). Maybe he'll write something about Maybe column types too. :-)

Also if you are interested in improving relational databases, Codd's 1979 paper "Extending the Database Relational Model to Capture More Meaning" is super interesting. The first part is where he adds NULLs (in order to add OUTER JOINs basically), but the second part is almost never mentioned and gives a way to query the schema itself as part of a database query. It looks a lot like doing graph database queries from your relational db. Also a better kind of EAV pattern. Also more support for OO-style inheritance. Somehow 40 years later it is still way more advanced than any existing RDBMS. It would totally break the parse-plan-execute pipeline of today's systems, but it is fascinating to think about. I wish more people would read this paper before trying to go "beyond relational"!