percival VS cozo

Souffle and Cozo mentioned below already implement the whole of "traditional" datalog.

Percival (https://github.com/ekzhang/percival) has some very nice examples showing how you can interactively write and test rules on top of a datalog interpreter.

Bud (http://bloom-lang.net/bud/) is Hellerstein's proof of concept playground. It has bit-rotted in the past few years, but the examples are readable even if you can't easily get it working.

The complexity can be quite good. You can syntactically determine when you've written linear recursion (equivalent to a for loop) vs not. Otherwise, the complexity is what you'd expect from incremental view maintenance in a normal SQL database. Which is to say O(n^k) with k being the number of relations joined, but usually much, much less with appropriate indexes and skew in the data. All the usual tricks concerning data normalization and indexes from databases apply.

I've worked on percival a bit, it compiles (transpiles?) the datalog ast into javascript code on demand and executes it to get the results, see [1]. Percival's creator, Eric, also submitted a 10m presentation about the project [2] to the HYTRADBOI 'virtual conference' earlier this year [2]. They also submitted a Show HN that received a couple comments [3]. The Have You Tried Rubbing A Database On It conference included several awesome presentations featuring datalog, which readers may find interesting [4].

[1]: https://github.com/ekzhang/percival/blob/main/crates/perciva...

[2]: https://www.hytradboi.com/2022/percival-a-reactive-language-...

[3]: https://news.ycombinator.com/item?id=29521975

[4]: https://www.hytradboi.com/

I haven't written a parser with Chumsky, bit I've played with a little one a bit if you wanna see an example syntax. The error reporting for this project is implemented with `ariadne` which is also really slick.

Parser: https://github.com/ekzhang/percival/blob/main/crates/perciva...

Error reporting: https://github.com/ekzhang/percival/blob/main/crates/perciva...

Datalog playground: https://percival.ink/

To see an error report, delete some punctuation from one of the Datalog code blocks then press shift-return.

Any thoughts on how your project will compare to CozoDB?

https://github.com/cozodb/cozo

I can figure parts of it out from https://github.com/cozodb/cozo/blob/main/cozo-core/tests/air_routes.rs which is enough to get started

I've been keeping an eye on https://github.com/cozodb/cozo which is pretty close to something I've wanted, a sqlite version of datalog/datomic.

Finally, the one product I was extremely impressed with and felt was genuinely impressive as a database in general was cozodb.

Take a look at cozodb. It meets most of your goals and I've been really enjoying using it. It might give you some inspiration or something to contribute to.

Sure. They're called 'partials' sometimes. Useful if you want to rerender just part of a page. This is a pattern used by HTMX, a 'js framework' that accepts fragments of html in an http response and injects it into the page. This is good because it avoids the flash and state loss of a whole page reload. See the HTMX essay on template fragments for a more complete argument [0].

This is a go template for an interactive todos app [1] that I'm experimenting with. The html content of the entire page is present in one template definition which is split into 6 inline {{block}} definitions / "fragments". The page supports 5 interactions indicated by {{define}} definitions, each of which reuse various block fragments relevant to that interaction. I'm in the process of converting it to use embedded cozodb [2] queries which act as a server side data store. The idea here is that the entire 'app', including all html fragments, styles, http requests and responses, db schema, and queries are embedded into this single 100-line file.

[0]: https://htmx.org/essays/template-fragments/

[1]: https://github.com/infogulch/go-htmx/blob/master/templates/t...

[2]: https://github.com/cozodb/cozo

If anyone wants to try a FOSS vector-relational-graph hybrid database for more complicated workloads than simple vector search, here it is: https://github.com/cozodb/cozo/

About the integrated vector search: https://docs.cozodb.org/en/latest/releases/v0.6.html

It also does duplicate detection (Minhash-LSH) and full-text search within the query language itself: https://docs.cozodb.org/en/latest/releases/v0.7.html

HN discussion a few days ago: https://news.ycombinator.com/item?id=35641164

Disclaimer: I wrote it.