Simon Willison’s Weblog

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cysqlite - a new sqlite driver (via) Charles Leifer has been maintaining pysqlite3 - a fork of the Python standard library's sqlite3 module that makes it much easier to run upgraded SQLite versions - since 2018.

He's been working on a ground-up Cython rewrite called cysqlite for almost as long, but it's finally at a stage where it's ready for people to try out.

The biggest change from the sqlite3 module involves transactions. Charles explains his discomfort with the sqlite3 implementation at length - that library provides two different variants neither of which exactly match the autocommit mechanism in SQLite itself.

I'm particularly excited about the support for custom virtual tables, a feature I'd love to see in sqlite3 itself.

cysqlite provides a Python extension compiled from C, which means it normally wouldn't be available in Pyodide. I set Claude Code on it and it built me cysqlite-0.1.4-cp311-cp311-emscripten_3_1_46_wasm32.whl, a 688KB wheel file with a WASM build of the library that can be loaded into Pyodide like this:

import micropip
await micropip.install(
    "https://simonw.github.io/research/cysqlite-wasm-wheel/cysqlite-0.1.4-cp311-cp311-emscripten_3_1_46_wasm32.whl"
)
import cysqlite
print(cysqlite.connect(":memory:").execute(
    "select sqlite_version()"
).fetchone())

(I also learned that wheels like this have to be built for the emscripten version used by that edition of Pyodide - my experimental wheel loads in Pyodide 0.25.1 but fails in 0.27.5 with a Wheel was built with Emscripten v3.1.46 but Pyodide was built with Emscripten v3.1.58 error.)

You can try my wheel in this new Pyodide REPL i had Claude build as a mobile-friendly alternative to Pyodide's own hosted console.

I also had Claude build this demo page that executes the original test suite in the browser and displays the results:

Screenshot of the cysqlite WebAssembly Demo page with a dark theme. Title reads "cysqlite — WebAssembly Demo" with subtitle "Testing cysqlite compiled to WebAssembly via Emscripten, running in Pyodide in the browser." Environment section shows Pyodide 0.25.1, Python 3.11.3, cysqlite 0.1.4, SQLite 3.51.2, Platform Emscripten-3.1.46-wasm32-32bit, Wheel file cysqlite-0.1.4-cp311-cp311-emscripten_3_1_46_wasm32.wh (truncated). A green progress bar shows "All 115 tests passed! (1 skipped)" at 100%, with Passed: 115, Failed: 0, Errors: 0, Skipped: 1, Total: 116. Test Results section lists TestBackup 1/1 passed, TestBlob 6/6 passed, TestCheckConnection 4/4 passed, TestDataTypesTableFunction 1/1 passed, all with green badges.

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