Stephane Faroult

This book is a sort of "companion" to The Art of SQL (same author).
While I appreciate the style and find it pretty useful, I am a bit disappointed for the choice of title (hence the 4 stars).

"Refactoring" is usually succinctly described as "improving quality without changing the behaviour of a given piece of code" - and in this sense the title is more or less adequate. The problem is that the only concept of "quality" in this case regards query efficiency.

I suppose this is more or less what show more a DBA or SQL expert really cares about, but if you expected patterns (and anti-patterns), the concept of code smells or - maybe more appropriately - how to incrementally redesign your tables to make them "better"... well, this book is not for you.

In fact you are probably looking for "Agile Database Techniques" or some other title. This one is 99% about query rewriting and maybe 1% of other techniques like change indexes or even restructure tables. But always and only in order to improve throughput.

If this is the type of "quality" you are concerned about, I doubt you can find something better. For a more balanced concept of "Refactoring" you should probably check some other book. show less

I got a lot out of the first half or so of this book. It did a great job helping me build a better mental model of how a database and query engine works internally, and what tradeoffs various techniques and design choices might be making. I wound up skimming some of the latter sections on data warehousing and relational tree building/querying techniques.

"The Art of SQL" was eye-opening. This book is for people who know SQL syntax but don't yet have a deep understanding of the implications of relational theory on how a functionally correct query can nonetheless be completely wrong (and have performance, scalability, and contention consequences). It has changed the way I think about structuring my queries and has helped me to write much better SQL than I did before.