Speaker Interview

Dimitri Fontaine

Hi! Could you briefly introduce yourself?

Hi! I am Dimitri Fontaine, and I’ve been contributing to PostgreSQL features such as Extensions support and Event Triggers. I also write and maintain the pgloader migration utility, that is meant to allow for a fully automated (as in CI/CD) migration from MySQL, MS SQL or SQLite to PostgreSQL.

I wrote a book that teaches SQL to developers, it’s available at masteringpostgresql.com.

I work at Citus Data, which nowadays means contributing to PostgreSQL from the Microsoft Azure Data team, the one that provides Open Source databases.

How do you engage with the PostgreSQL community?

Nowadays mostly through going to conferences, thanks to my employer. When speaking, I focus on spreading good news and knowledge about PostgreSQL, targeting those who have the most to benefit from our favorite RDBMS: developers.

I also publish the pgloader utility as an Open Source software (same licence as PostgreSQL itself): pgloader loads data into PostgreSQL from many different sources, including other database systems. It allows to implement Continuous Migration in a fully automated way.

Have you enjoyed previous pgDay Paris or other PostgreSQL Europe conferences, either as attendee or as speaker?

I’ve been to every PGConf.EU conference but one, and spoke at almost all of them. I’ve been to every pgDay Paris conference, and I really enjoy that one. pgDay Paris is a well organized one-day one-track conference, and allows to meet with French users, corporate and start-ups, in a nice setting.

What will your talk be about, exactly? Why this topic?

My talk is entitled “How to write an SQL query”. The goal is to show the process involved in writing a query. We often share a SQL query in its final form, which could be quite simple or quite advanced. We rarely spend enough time on explaining the process behind writing those SQL queries. It’s an interactive process where each step makes progress on top of the previous one, and that’s what I am going to talk about!

What is the audience for your talk?

Anyone who has to write a SQL query and sometimes wonder either where to start, or where to stop and continue writing code in the application layer calling the SQL query instead. Or sometimes wonder about both.

Which would be application developers, ops people, DBAs too. Data analysts and AI folks also. Basically, anyone who’s written an SQL query before…

What existing knowledge should the attendee have in order to follow your talk?

Having already written a couple SQL queries and wondered about the syntax, the SQL feature set or how to do that thing is a pre-requisite. If you have ever typed an SQL query and didn’t know how to fix this strange error message, then you know that talk is for you!

Which missing feature would you most like to see in PostgreSQL?

Well the next one on my list would be timetravel, also known as periods, also known as AS OF. Also global temporary tables would be nice to have: at least being able to use temporary tables without any catalog churn, that’d be something…

There’s more to it, and that’s a good start already.

Can you tell us more about your book, “Mastering PostgreSQL for Application Developers”, and specifically about the “Mastering” part?

The idea is that “Mastering” is a process that happens a day at a time. When practicing an intrument, be it the guitar or piano, violin or drums, it’s pretty obvious for anyone that you need years of daily deliberate practice before you’re any good at it.

Well for SQL and many other tooling, it’s the same thing. The only way to someday master SQL is to practice daily. I’ve written my book with the idea to help application developers improve their SQL skills. The book tries to show how to answer many simple business questions all at the SQL prompt.

If you try to answer one or maybe two such questions every day, doing it all in SQL, you will see your skill set improve dramatically. Then SQL becomes an asset you know how to benefit from, and how to make the best use of in your application code. “Mastering PostgreSQL in application development” is written with that idea in mind.

Thank you!