percival
prql
percival | prql | |
---|---|---|
12 | 106 | |
571 | 9,436 | |
- | 0.8% | |
0.0 | 9.9 | |
about 1 year ago | 6 days ago | |
Rust | Rust | |
MIT License | Apache License 2.0 |
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percival
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Learn Datalog Today
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.
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Soufflé: A Datalog Synthesis Tool for Static Analysis
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/
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Chumsky, a Rust parser-combinator library with error recovery
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.
- Show HN: Percival – Web-based reactive Datalog notebooks, made with Rust+Svelte
- Percival: Web-based, reactive Datalog notebooks for data analysis and visualization, written in Rust and Svelte
prql
- Prolog language for PostgreSQL proof of concept
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SQL is syntactic sugar for relational algebra
> I completely attribute this to SQL being difficult or "backwards" to parse. I mean backwards in the way that in SQL you start with what you want first (the SELECT) rather than what you have and widdling it down.
> The turning point for me was to just accept SQL for what it is.
Or just write PRQL and compile it to SQL
https://github.com/PRQL/prql
- Transpile Any SQL to PostgreSQL Dialect
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Show HN: Open-source, browser-local data exploration using DuckDB-WASM and PRQL
Hey HN! We’ve built Pretzel, an open-source data exploration and visualization tool that runs fully in the browser and can handle large files (200 MB CSV on my 8gb MacBook air is snappy). It’s also reactive - so if, for example, you change a filter, all the data transform blocks after it re-evaluate automatically. You can try it here: https://pretzelai.github.io/ (static hosted webpage) or see a demo video here: https://www.youtube.com/watch?v=73wNEun_L7w
You can play with the demo CSV that’s pre-loaded (GitHub data of text-editor adjacent projects) or upload your own CSV/XLSX file. The tool runs fully in-browser—you can disconnect from the internet once the website loads—so feel free to use sensitive data if you like.
Here’s how it works: You upload a CSV file and then, explore your data as a series of successive data transforms and plots. For example, you might: (1) Remove some columns; (2) Apply some filters (remove nulls, remove outliers, restrict time range etc); (3) Do a pivot (i.e, a group-by but fancier); (4) Plot a chart; (5) Download the chart and the the transformed data. See screenshot: https://imgur.com/a/qO4yURI
In the UI, each transform step appears as a “Block”. You can always see the result of the full transform in a table on the right. The transform blocks are editable - for instance in the example above, you can go to step 2, change some filters and the reactivity will take care of re-computing all the cells that follow, including the charts.
We wanted Pretzel to run locally in the browser and be extremely performant on large files. So, we parse CSVs with the fastest CSV parser (uDSV: https://github.com/leeoniya/uDSV) and use DuckDB-Wasm (https://github.com/duckdb/duckdb-wasm) to do all the heavy lifting of processing the data. We also wanted to allow for chained data transformations where each new block operates on the result of the previous block. For this, we’re using PRQL (https://prql-lang.org/) since it maps 1-1 with chained data transform blocks - each block maps to a chunk of PRQL which when combined, describes the full data transform chain. (PRQL doesn’t support DuckDB’s Pivot statement though so we had to make some CTE based hacks).
There’s also an AI block: This is the only (optional) feature that requires an internet connection but we’re working on adding local model support via Ollama. For now, you can use your own OpenAI API key or use an AI server we provide (GPT4 proxy; it’s loaded with a few credits), specify a transform in plain english and get back the SQL for the transform which you can edit.
Our roadmap includes allowing API calls to create new columns; support for an SQL block with nice autocomplete features, and a Python block (using Pyodide to run Python in the browser) on the results of the data transforms, much like a jupyter notebook.
There’s two of us and we’ve only spent about a week coding this and fixing major bugs so there are still some bugs to iron out. We’d love for you to try this and to get your feedback!
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Pql, a pipelined query language that compiles to SQL (written in Go)
> Looks like PRQL doesn't have a Go library so I guess they just really wanted something in Go?
There's some C bindings and the example in the README shows integration with Go:
https://github.com/PRQL/prql/tree/main/prqlc/bindings/prqlc-...
- FLaNK Stack 26 February 2024
- FLaNK Stack Weekly 19 Feb 2024
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PRQL as a DuckDB Extension
Can someone tell me why PRQL is better? I went here: https://github.com/PRQL/prql
It looks nice, but what's the strengths compared to SQL?
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Shouldn't FROM come before SELECT in SQL?
PRQL [1] is a compile-to-SQL relational querying language that puts FROM first.
[1] https://prql-lang.org
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Vanna.ai: Chat with your SQL database
https://prql-lang.org/ might be an answer for this. As a cross-database pipelined language, it would allow RAG to be intermixed with the query, and the syntax may(?) be more reliable to generate
What are some alternatives?
codeql - CodeQL: the libraries and queries that power security researchers around the world, as well as code scanning in GitHub Advanced Security
malloy - Malloy is an experimental language for describing data relationships and transformations.
crepe - Datalog compiler embedded in Rust as a procedural macro
Preql - An interpreted relational query language that compiles to SQL.
modus - A language for building Docker/OCI container images
bustub - The BusTub Relational Database Management System (Educational)
cclyzerpp - cclyzer++ is a precise and scalable pointer analysis for LLVM code.
tresql - Shorthand SQL/JDBC wrapper language, providing nested results as JSON and more
souffle - Soufflé is a variant of Datalog for tool designers crafting analyses in Horn clauses. Soufflé synthesizes a native parallel C++ program from a logic specification.
spyql - Query data on the command line with SQL-like SELECTs powered by Python expressions
async-observable - Async & reactive synchronization model to keep multiple async tasks / threads partially synchronized.
toydb - Distributed SQL database in Rust, written as a learning project