pyDatalog 0.21.0

A pure-python implementation of Datalog, a truly declarative language derived from Prolog.

pyDatalog

[!NOTE] In view of the 300 stars on GitHub (Thanks !!), I have restarted support of this package in June 2026.

Installation

You can install pyDatalog from PyPI using pip:

pip install pyDatalog

Or using uv:

uv add pyDatalog

[!NOTE] Pre-compiled binary wheels are provided for most common platforms and Python versions. A pure Python wheel is also published on PyPI for universal compatibility. If a platform-specific wheel is not available, your package manager (like pip or micropip) will automatically install the pure Python wheel, which runs natively on WebAssembly/Pyodide, mobile environments (like Pydroid 3), and all other architectures without requiring a C compiler. If installation is requested from source (instead of from wheels) and fails, the library will gracefully fall back to its pure-Python implementation.

Description

pyDatalog adds the logic programming paradigm to Python's toolbox, in a pythonic way. You can now run logic queries on databases or Python objects, and use logic clauses to define python classes. In particular, pyDatalog can be used as a query language:

• it can perform multi-database queries (from memory datastore, 11 relational databases, and noSQL database with appropriate connectors)
• it is more expressive than SQL, with a cleaner syntax;
• it facilitates re-use of SQL code snippet (e.g. for frequent joins or formula);

Datalog = SQL + recursivity

Datalog is a truly declarative language derived from Prolog, with strong academic foundations. It complements Python very well for:

• managing complex sets of related information (e.g. in data integration or the semantic web).
• simulating intelligent behavior (e.g. in games),
• performing recursive algorithms (e.g. in network protocol, code and graph analysis, parsing)
• solving discrete constraint problems.

As simple as Excel

Datalog excels at accelerated development: Datalog programs are often shorter than their Python equivalent, and Datalog statements can be specified in any order, as simply as formula in a spreadsheet.

Testimonials

pyDatalog is cited in several scientific papers !

"Very neat. Datalog rocks" - Marck Carter. He has written a nice blog entry on unit conversion with Datalog.

"Congratulations for your wonderful work done in pyDatalog project" - Karamajit Kaur, researcher in India

You are also using pyDatalog ? Let us know.