What exactly are keyed tables?

Note: You can now subscribe to our YouTube video channel for q/kdb+ tutorials. Well, I will tell you what they are not – tables! If you take away one thing from this post, it’s that keyed tables are poorly named and are not tables. However, after reading this post, you should have a better understanding …

Understanding type casting in q

This post is a follow up to the previous post about datatypes in q. In that post, I went over all the datatypes available in q and how to identify them using character, numeric, or symbol representation. Now, we are ready to discuss another important topic in q: type casting. This post is also available …

Getting started with data science

Recently, a few of my friends have shown interest in what I do and the skill set required for my job. For those who don’t know, I am a market data developer. This means that I work with time-series databases to capture and store both real-time and historical data. I am also responsible for writing …

qSQL queries for performing analytics

I realize that there are many developers out there that are not looking to get into q completely and are simply using q/kdb+ along with qsql to perform analytics (i.e. quants). My job requires all of this so I have some good experience running qsql queries. Of course, the type of query you need to …

Overview of kdb+ architecture

So far, I have covered quite a few intermediate topics without covering the basics. In this post, I would like to take a step back and talk about general architecture of kdb+. A simple kdb+ setup includes a feed handler (fh), a ticker plant (tp), a real-time database (rdb), and a historical database (hdb). These processes work …

Tables, keyed tables and dictionaries

When I first started learning q, I had a difficult time understanding the differences between tables, keyed tables and dictionaries. The differences seemed very subtle at the time. Just recently, I was explaining a colleague (java developer with some exposure to q/kdb) how you can check meta of a table, look up the keys and …