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Databases & Data

The most popular blog posts about databases & data on Hacker News. 138 posts.

2021
93

A Data Pipeline Is a Materialized View

Say you run an online book store and want to build a data pipeline that figures out who the top-selling authors are. Logically, the input to the pipeline is a log of every individual book purchase on the store for all time, along with details about each book like who authored it. And the output is a list of the…

94

Git as a NoSql Database (2016)

Git’s man-pages state that it’s a stupid content tracker. It’s probably the most used version control system in the world. Which is very strange, since it doesn’t describe itself as being a source control system. And in fact, you can use git to track any

101

One of these JPEGs is not like the other

“JPEG” or the image encoding specification by the “Joint Photographic Experts Group” (JPEG) is a truly universal format at this stage. You really cannot go very far on the internet without seeing a JPEG file. The amount of content encoded in JPEGs must be surely biblical by now. If there is one thing that is going to…

103

SQLite Is Dynamically Typed (2020)

A small, cool fact about SQLite is that its columns are flexibly typed. You can store any value in any column! Try it out: sqlite> create table t1 (v1 int, v2 varchar(10)); sqlite> insert into t1 values ("abc", "this string is longer than 10 characters!"); sqlite> select * from t1; abc|this string is longer than 10…

119

Why query planning for streaming systems is hard

Many groups are working on running sql queries in incremental/streaming systems . Query planning in this context is not a well understood problem. This post is a quick pointer towards the many open problems. It's not intended to be complete or authoritative, because I haven't engaged with the problem much beyond…