Harry R. Schwartz

Code writer, sometime Internet enthusiast, attractive nuisance.

The author at the Palais du Luxembourg in Paris, November 2022. hacker news gitlab sourcehut pinboard librarything 1B41 8F2C 23DE DD9C 807E A74F 841B 3DAE 25AE 721B


British Columbia



Datalog User Manual


Published .
Tags: computer-science.

Datalog is a declarative programming language. It’s a strict subset of Prolog, with a couple slick properties:

  • Its queries are guaranteed to terminate (so it’s not Turing-complete).
  • Query evaluation is sound and complete.

That’s (usually) exactly what you want out of a simple query language. As such, it’s been getting some not-just-academic interest in the last few of years, most notably as the query language for Datomic.

I got kinda interested in Datalog a year or so ago. I started out by reading the Datalog User Manual, which is a nice introduction to the language. However, the manual’s only available as a website, so I went on a brief yak-shaving expedition and converted it to epub, mobi, and pdf.

If you’re interested in learning Datalog and also don’t like doing your long-form reading in a web browser, give it a read!

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