Obviously I'm not entitled to tell anyone how to design their databases. I'm just saying there's good reasons why so many DBs stick to a SQL-like syntax, and that is because the alternatives are usually worse (think: familiarity, tooling, scripting, REPL, etc.).

For example, using the MongoDB REPL, which is probably close to what a datalog-REPL would look like, is rather painful.

This may all be a non-issue when a LISP-language is exclusively used on the client-side. That query-style probably just snaps in naturally there (I don't know lisp).

But if the database is supposed to be general purpose, accessed with lesser languages, scripted, quickly fixed by half-drunk humans at 4am in a REPL... then it certainly matters to have a sane intermediate lingo. Otherwise, at the least, every client-platform is going to invent their own.

I think the example of Cassandra is really a good one to study. They went through an interesting learning-process that seems very applicable here.

Edit: Please see my other comment above. It seems I have misunderstood the project goals and this is in fact not meant to become a general purpose DB. Under that premise my concerns obviously don't apply...

I made my first comments under the assumption that this aims to be a general purpose database, but multiple people have made clear now that this is not the case.

Obviously it makes no sense to argue for an intermediate QL (and one as half-baked as SQL) when the project is ultimately aimed at Lisp-purists[1].

[1] This is not meant derogatory, it's just a critical distinction from a DB that, say, my junior-admin who knows his SQL and Python and not much else could be expected to get along with.