Dimitri Fontaine - Mastering PostgreSQL in Application Development

First of all, I'd like to thank all the contributors to the book. I know they all had other priorities in life, yet they found enough time to contribute and help make this book as good as I could ever hope for, maybe even better!

I'd like to give special thanks to my friend Julien Danjou who's acted as a mentor over the course of writing of the book. His advice about every part of the process has been of great value maybe the one piece of advice that I most took to the heart has been write the book you wanted to read.

Id also like to extend my thanks to the people interviewed for this book. In order of appearance, they are Yohann Gabory from the French book Django Avanc, Markus Winand from http://use-the-index-luke.com and http://modern-sql.com, Grgoire Hubert author of the PHP POMM project, lvaro Hernndez Tortosa who created ToroDB, bringing MongoDB to SQL, and Kris Jenkins, functional programmer and author of the YeSQL library for Clojure.

Having insights from SQL users from many different backgrounds has been valuable in achieving one of the major goals of this book: encouraging you, valued readers, to extend your thinking to new horizons. Of course, the horizons Im referring to include SQL.

I also want to warmly thank the PostgreSQL community. If you've ever joined a PostgreSQL community conference, or even asked questions on the mailing list, you know these people are both incredibly smart and extremely friendly. Its no wonder that PostgreSQL is such a great product as it's produced by an excellent group of well-meaning people who are highly skilled and deeply motivated to solve actual users problems.

Finally, thank you dear reader for having picked this book to read. I hope that youll have a good time as you read through the many pages, and that you'll learn a lot along the way!

SQL stands for Structured Query Language; the term defines a declarative programming language. As a user, we declare the result we want to obtain in terms of a data processing pipeline that is executed against a known database model and a dataset.

The database model has to be statically declared so that we know the type of every bit of data involved at the time the query is carried out. A query result set defines a relation, of a type determined or inferred when parsing the query.

When working with SQL, as a developer we relatedly work with a type system and a kind of relational algebra. We write code to retrieve and process the data we are interested into, in the specific way we need.

RDBMS and SQL are forcing developers to think in terms of data structure, and to declare both the data structure and the data set we want to obtain via our queries.

Some might then say that SQL forces us to be good developers: