Hacker News Reader

Well, there's K, along with its flagship database KDB which lets you write SQL-like queries and, from what I've heard, integrates very nicely with the language. idk how good their FFI story is. Unfortunately, you need to pay for commercial use.

You can extend kdb with c functions, but they need to take/return their internal K structures, so you'll need to wrap functions. `2:` is the thing to look at.

Otherwise there's ipc clients, and a very nice native python integration now.

Not exactly what you want, but you may want to check out F# type providers..

Dyalog has a web server and a fully documented SQL library.