You're right, and I think a lot of data structures (all of them?) can be seen as special cases of relational databases. I also feel like there are similarities

You're right, and I think a lot of data structures (all of them?) can be seen as special cases of relational databases. I also feel like there are similarities to logic programming languages like Prolog and Datalog, and a language that combined them while still allowing the programmer to finely tune performance through explicit hints could be powerful.