Generating Random Numbers According to a Continious Probability Distribution with PostgreSQL

When working with statistics, generating pseudo-random samples that are distributed according to a given probability distribution is a frequent requirement. For me, being able to generate these numbers directly with SQL would be very convenient (and might also improve performance). In this post, I’m taking a look at some of the most important continious probability distributions…

  ·  Christoph Schiessl on PostgreSQL

Benchmark: Single-Column Indexes vs. Compound Indexes

I’ve known about compound indexes for many years but never really thought about them in detail. That doesn’t mean, I’ve never used them – quite on the contrary. At some point in the past I’ve made up some assumptions about when to use them and when to avoid them. However, until now I’ve never taken the time to put my assumptions to the test.

  ·  Christoph Schiessl on PostgreSQL

Organizing Java Command-Line Utilities with the Command Pattern

I’m currently working on a command-line utility written in Java to encapsulate a WSDL web service. As you might expect, the web service is exposing a variety of operations with pre-defined parameters to be called. My tool should make these operations accessible to the user, through an easy-to-use command-line interface. Since the web service I’m working with is composed of dozens of operations, I started looking for a design pattern to help me organize my code and discovered the Command Pattern.

  ·  Christoph Schiessl on Java | Pattern

Simplicity Isn’t Simple

Everybody is talking about simplicity and its promise of leading us to create great products. The underlying assumption here is, that simpler products are more accessible to everyone: the customers, the users, and last but not least the developers themselves. Therefore, simple products are supposed to be easier to sell, a lot easier to use, and easier to maintain.

  ·  Christoph Schiessl on Business | Software

Software Start-Ups without Technical Co-Founders

Software start-ups are everywhere. Every single day, you can read about dozens of new and ambitious start-ups in the news. There are many special websites to report about start-ups and other topics that entrepreneurs and developers might be interested in – yes, I’m looking at you HackerNews.

  ·  Christoph Schiessl on Business

Customers and Users Are Not The Same!

A few weeks ago, I discovered a fatal flaw in my thinking about customers, users and consequently about marketing in general. To fix that flaw, I had to reevaluate the feature set of my products as well as my entire approach to communicating with (potential) customers.

  ·  Christoph Schiessl on Business