Simon Willison’s Weblog

53 items tagged “sqlite”

Slides, notes and links from my Datasette talk at PyBay (via) I presented a session about Datasette at the PyBay conference in San Francisco this morning. I talked about the project itself and demonstrated ways of creating and publishing databases using csvs-to-sqlite, Datasette Publish and my new sqlite-utils library. # 19th August 2018, 11:23 pm

Compiling SQLite for use with Python Applications (via) Charles Leifer’s recent tutorial on how to compile and build the latest SQLite (with window function support) for use from Python via his pysqlite3 library. # 15th August 2018, 3:51 pm

coleifer/pysqlite3. Now that the pysqlite package is bundled as part of the Python standard library the original open source project is no longer actively maintained, and has not been upgraded for Python 3. Charles Leifer has been working on pysqlite3, a stand-alone package of the module. Crucially, this should enable compiling the latest version of SQLite (via the amalgamation package) without needing to upgrade the version that ships with the operating system. # 15th August 2018, 3:15 pm

Window Functions in SQLite 3.25.0. The next release of SQLite (apparently die for release in September) will add window functions, as specified in various SQL standards and already available in PostgreSQL. This is going to dramatically improve SQLite as an engine for performing analytical queries, especially across time series data. It’s also going to further emphasize the need for people to be able to upgrade their SQLite versions beyond those provided by the operating system—the default Ubuntu run by Travis CI still only ships with SQLite 3.8 for example. # 15th August 2018, 3:12 pm

Datasette unit tests: monkeytype_call_traces (via) Faceted browse against every function call that occurs during the execution of Datasette’s test suite. I used Instagram’s MonkeyType tool to generate this, which can run Python code and generates a SQLite database of all of the traced calls. It’s intended to be used to automatically add mypy annotations to your code, but since it produces a SQLite database as a by-product I’ve started exploring the intermediary format using Datasette. Generating this was as easy as running “monkeytype run `which pytest`” in the Datasette root directory. # 2nd August 2018, 9:03 pm

ActorDB. Distributed SQL database written in Erlang built on top of SQLite (on top of LMDB), adding replication using the raft consensus algorithm (so sharded with no single-points of failure) and a MySQL protocol interface. Interesting combination of technologies. # 24th June 2018, 9:48 pm

Query Parquet files in SQLite. Colin Dellow built a SQLite virtual table extension that lets you query Parquet files directly using SQL. Parquet is interesting because it’s a columnar format that dramatically reduces the space needed to store tables with lots of duplicate column data—most CSV files, for example. Colin reports being able to shrink a 1291 MB CSV file from the Canadian census to an equivalent Parquet file weighing just 42MB (3% of the original)—then running a complex query against the data in just 60ms. I’d love to see someone get this extension working with Datasette. # 24th June 2018, 7:44 pm

SpatiaLite — Datasette documentation. Datasette’s documentation now includes extensive coverage of the SpatiaLite extension for SQLite: how to install it, how to import latitude/longitude points, shapefiles and GeoJSON data into SpatiaLite tables, and how to run SQL queries against it that take advantage of spatial indexes. I’m learning SpatiaLite at the moment and filling out the documentation with each new trick I learn as I go—as Mark Pilgrim once taught me, the best way to learn a new technology is to write about it. # 30th May 2018, 4:34 am

Library of Congress Sustainability of Digital Formats: SQLite. “The Library of Congress Recommended Formats Statement (RFS) includes SQLite as a preferred format for datasets.” # 28th May 2018, 5:19 pm

VirtualKNN for SpatiaLite. This looks amazing: a special virtual table shipped as part of SpatiaLite 4.4.0 which implements a fast, R-Tree backed mechanism for finding the X nearest points against a geospatial database table. There’s just one catch: it’s only available in 4.4.0, but the most recent “stable” release of SpatiaLite is 4.3.0a from September 2015 so the version you get if you install from apt-get or homebrew doesn’t yet have this functionality. I’d love to figure out a neat way to package and distribute this along with Datasette. I’d also like to figure out a clean way to ship a more recent version of SQLite than the one that is currently packaged with Python 3 (3.16.2, where the latest SQLite release is 3.23.1). # 21st May 2018, 9:23 pm

sqlitebiter. SImilar to my csvs-to-sqlite tool, but sqlitebiter handles “CSV/Excel/HTML/JSON/LTSV/Markdown/SQLite/SSV/TSV/Google-Sheets”. Most interestingly, it works against HTML pages—run “sqlitebiter -v url ’’” and it will scrape that Wikipedia page and create a SQLite table for each of the HTML tables it finds there. # 17th May 2018, 10:40 pm

sql.js Online SQL interpreter (via) This is fascinating: sql.js is a project that complies the whole of SQLite to JavaScript using Emscripten. The demo is an online SQL interpreter which lets you import an existing SQLite database from your filesystem and run queries against it directly in your browser. # 17th May 2018, 9:28 pm

Datasette: Full-text search. I wrote some documentation for Datasette’s full-text search feature, which detects tables which have been configured to use the SQLite FTS module and adds a search input box and support for a _search= querystring parameter. # 12th May 2018, 12:09 pm

The latest SQLite 3.8.7 alpha version is 50% faster than the 3.7.17 release from 16 months ago.  That is to say, it does 50% more work using the same number of CPU cycles. [...] The 50% faster number above is not about better query plans.  This is 50% faster at the low-level grunt work of moving bits on and off disk and search b-trees.  We have achieved this by incorporating hundreds of micro-optimizations.  Each micro-optimization might improve the performance by as little as 0.05%.  If we get one that improves performance by 0.25%, that is considered a huge win.  Each of these optimizations is unmeasurable on a real-world system (we have to use cachegrind to get repeatable run-times) but if you do enough of them, they add up.

D. Richard Hipp # 10th May 2018, 5:15 am

Notes from my appearance on the Changelog podcast

After I spoke at Zeit Day SF last weekend I sat down with Adam Stacoviak to record a 25 minute segment for episode 296 of the Changelog podcast, talking about Datasette. We covered a lot of ground!

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Exploring the UK Register of Members Interests with SQL and Datasette

Ever wondered which UK Members of Parliament get gifted the most helicopter rides? How about which MPs have been given Christmas hampers by the Sultan of Brunei? (David Cameron, William Hague and Michael Howard apparently). Here’s how to dig through the Register of Members Interests using SQL and Datasette.

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csvs-to-sqlite 0.8. I released a new version of my csvs-to-sqlite tool this morning with a bunch of handy new features. It can now rename columns and define their types, add the CSV filenames as an additional column, add create indexes on columns and parse dates and datetimes into SQLite-friendly ISO formatted values. # 24th April 2018, 4:11 pm

How I made a Who’s On First subset database. Inspired by Paul Ford on Twitter, I tried out a new trick with SQLite: connect to a database containing JSON, attach a brand new empty database file using “attach database”, then populate it using INSERT INTO ... SELECT plus the json_extract() function to extract out a subset of the JSON properties into a new table in the new database. # 3rd February 2018, 5:25 am

[On SQLite] The JSON interface is like, “we save the text and when you retrieve it we parse the JSON at several hundred MB/s and let you do path queries against it please stop overthinking it, this is filing cabinet.”

Paul Ford # 29th January 2018, 4:29 pm

SQLite: The Spellfix1 Virtual Table (via) A SQLite extension that lets you create a spellfix1 virtual table which can power “fuzzy” search, by suggesting corrections for misspelled words. I haven’t tried this yet but it looks pretty powerful, including a configurable edit distance and the ability to set up custom “soundslike” terms for words with known unusual spellings. # 29th January 2018, 5:24 am

Analyzing my Twitter followers with Datasette

I decided to do some ad-hoc analsis of my social network on Twitter this afternoon… and since everything is more fun if you bundle it up into a SQLite database and publish it to the internet I performed the analysis using Datasette.

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How to turn a list of JSON objects into a Datasette. ramadis on GitHub cleaned up data on 184,879 crimes reported in Buenos Aires since 2016 and shared them on GitHub as a JSON file. Here are my notes on how to use Pandas to convert JSON into SQLite and publish it using Datasette. # 20th January 2018, 1:07 am

How to compile and run the SQLite JSON1 extension on OS X. Thanks, Stack Overflow! I’ve been battling this one for a while—it turns out you can download the SQLite source bundle, compile just the json1.c file using gcc and load that extension in Python’s sqlite3 module (or with Datasette’s --load-extension= option) to gain access to the full suite of SQLite JSON functions—json(), json_extract() etc. # 10th January 2018, 9:01 pm

Building a location to time zone API with SpatiaLite, OpenStreetMap and Datasette

Given a latitude and longitude, how can we tell what time zone that point lies within? Here’s how I built a simple JSON API to answer that question, using a combination of data from OpenStreetMap, the SpatiaLite extension for SQLite and my Datasette API tool.

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Big Data Workflow with Pandas and SQLite (via) Handy tutorial on dealing with larger data (in this case a 3.9GB CSV file) by incrementally loading it into pandas and writing it out to SQLite. # 28th November 2017, 11:02 pm

Many Small Queries Are Efficient In SQLite. Since SQLite runs in-process rather than being accessed over a network it avoids the per-query overhead of network round trips. This means that while MySQL or PostgreSQL applications need to avoid N+1 query patterns that create 100s of queries per request, SQLite apps can be designed differently: provided you hit indexes or small tables, 200 queries just means 200 extra cheap function calls. # 26th November 2017, 4:24 pm

SQLite Query Language: WITH clause. SQLite’s documentation on recursive CTEs starts out with some nice clear examples of tree traversal using a WITH statement, then gets into graphs, then goes way off the deep end with a Mandelbrot Set query and a query that can solve Soduku puzzles (“in less than 300 milliseconds on a modern workstation”). # 26th November 2017, 7:23 am

New in Datasette: filters, foreign keys and search

I’ve released Datasette 0.13 with a number of exciting new features (Datasette previously).

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harelba/q (via) q is a neat command-line utility that lets you run SQL queries directly against CSV and TSV files. Internally it works by firing up an in-memory SQLite database, and as of the latest release (1.7.1) you can use the new --save-db-to-disk option to save that in-memory database to disk. # 25th November 2017, 5:49 pm

Datasette: instantly create and publish an API for your SQLite databases

I just shipped the first public version of datasette, a new tool for creating and publishing JSON APIs for SQLite databases.

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