Category: StackOverflow

Related to help on stackoverflow

Eight Years on SO

After eight years on StackOverflow and more than 600 answers, these are my favourite three.

  1. How to understand the fifth normal form? [🔗]
  2. Composite primary key vs. an additional ID column. [🔗]
  3. How to design this database to avoid the cyclic dependency? [🔗]

These are not the highest voted answers, but I like them. All three rely on basic time-tested knowledge and principles, favour simplicity and reasoning over confusion and technical trickery.

Few Changes

Over the last few years, I was too busy to work on a blog — when I found some time I published on StackOverflow. I do plan to activate this blog again, will publish some ideas and tricks I have learned along the way.

I used to have a MediaWiki installation as a knowledge base for certain projects. However, due to large amount and persistence of spam I had to shut it down.

All traffic is now over HTTPS, and I have removed any video links that require Flash. The comments are disabled, so this will be just a read-only site. This way it is easier to deter spam and at least minimize user tracking. As far as cookies and tracking is concerned, I did the best I could — take a look at Cookies & Privacy.

Observation Pattern

The post relates to a stackoverflow question on DB design and my answer there.

To summarize relationships:

  • One report can list many observations, an observation can appear in many reports.
  • One subject (under observation) can undergo many observations, an observation relates to one subject only.
  • An observation is of a specific type, there can be many observations of the same type.
  • Measurement and trait are types of observations. Measurement is a numeric observation, like height. Trait is a descriptive observation, like color.

This is a simplified model based on Fowler’s observation pattern, for more details see Analysis Patterns by Martin Fowler.