Mastering PostgreSQL in Application Development is intended for developers working on applications that use a database server and covers advanced SQL techniques for data processing. The book addresses specifically the PostgreSQL RDBMS and answers practical questions every developer is confronted with when using PostgreSQL. You will learn best practices that help with integrating SQL into your own workflow, and through the many examples provided, you’ll see all the reasons why you might be interested in doing more in SQL. Primarily, it means writing fewer lines of code.
The book is a poorly structured mix of wikipedia quotes, PostgreSQL documentation excerpts and random author's thought. If you ever read a book or online course on databases, you most likely had the exact same structure and 90% same content.
It could've been more helpful if it would skip all the "Databases 101" content and kept only specific PostgreSQL parts. Also the book lacked any practical exercices which could help to solidify material.
The chapters on data modelling and concurrency are okay though.
This is neat to learn a few SQL tricks and deepen your understanding, but quite honestly, the amount of errors in the version I had (granted it was the first version) was very distracting. I also could not discern a particular goal/thesis that this book was getting at. I think Dimitri Fontaine is clearly an absolute pro and has incredible knowledge, but this book, to me (a junior dev), is not easy to read or take anything home from. What I did learn is that it is OK, and sometimes even really good, to have business logic in SQL.