Pandas is by far the most popular tool for data analysis. It's packed with useful features, it's battle tested and widely accepted. However, pandas comes at a cost which is often overlooked. SQL databases has been around since the 1970s. They contain many features that most developers never heard of, and I want to bring some of them to light.
Django 3.2 is just around the corner and it's packed with new features. Django versions are usually not that exciting (it's a good thing!), but this time many features were added to the ORM, so I find it especially interesting!
In this article I describe the process we took to identify potential free space, and one surprising find that helped up clear up ~10GB of unused indexed values!
There is a type of index you are probably not using, and may have never even heard of. It is wildly unpopular, and until a few PostgreSQL versions ago it was highly discouraged and borderline unusable, but under some circumstances it can out-perform even a B-Tree index.
What if mypy could warn you about possible problems at "compile time"? In this article I share a little trick to get mypy to fail when a value in an enumeration type is left unhandled.
Any database schema is likely to have plenty of text fields. In this article I demonstrate the surprising impact of medium-size texts on query performance.
Many developers think that having a critical bug in their code is the worse thing that can happen. Well, there is something much worst than that: Having a critical bug in your code and not knowing about it! Using some high school level statistics and a fair knowledge of SQL, I implemented a very simple anomaly detection system.
Some tips and misconceptions about database development I gathered along the way.
If you ever had a test that one day just started to fail, unprovoked, or a test that fails once every blue moon for no apparent reason, it's possible your code is relying on something that is not deterministic. In this article I describe a practical approach to dependency injection in Python that when used correctly, can eliminate nondeterminism and make your code easier to maintain and to test.
In my latest article for RealPython I cover some exotic migration operations, many of the built-in migration CLI commands and demonstrate important migrations concepts such as reversible migrations, migration plans and introspection.
