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Databases & Data

The most popular blog posts about databases & data on Hacker News. 4,222 posts.

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556

Command-line tools for data science

Blog article by Jeroen Janssens. Sep 19, 2013. 21 min read. Data science is OSEMN (pronounced as awesome). That is, it involves Obtaining, Scrubbing, Exploring, Modelling, and iNterpreting data. As a data scientist, I spend quite a bit of time on the command-line, especially when there’s data to be obtained, scrubbed…

560

Interesting data structures: the BK-tree

A BK-tree is a tree data structure specialized to index data in a metric space . A metric space is essentially a set of objects which we equip with a distance function $d(a, b)$ for every pair of elements $(a, b)$. This distance function must satisfy a set of axioms in order to ensure it’s well-behaved. The exact…

564

Working with time in Postgres

A massive amount of reporting queries, whether really intensive data analysis, or just basic insights into your business involving looking at data over a certain time period. Postgres has really rich support for dealing with time out of the box, something that’s often very underweighted when dealing with a database…

566

Unlearning descriptive statistics

If you've ever used an arithmetic mean, a Pearson correlation or a standard deviation to describe a dataset, I'm writing this for you. Better numbers exist to summarize location, association and spread: numbers that are easier to interpret and that don't act up with wonky data and outliers.

569

How to visualize decision trees

Decision trees are the fundamental building block of gradient boosting machines and Random Forests(tm), probably the two most popular machine learning models for structured data. Visualizing decision trees is a tremendous aid when learning how these models work and when interpreting models. Unfortunately, current…

570

Amazon Aurora Now Available

We announced Amazon Aurora last year at AWS re:Invent (see Amazon Aurora – New Cost-Effective MySQL-Compatible Database Engine for Amazon for more info). With storage replicated both within and across three Availability Zones, along with an update model driven by quorum writes, Amazon Aurora is designed to deliver…