In the previous post we introduced the PostgreSQL’s dependency system.

At first sight the implementation can look like a maze where the succession of relationships are not clear.

This post will try to give a practical example to show how pg_depend can act like an Ariadne’s thread in order to resolve the dependencies.

The scenario presented is very simple but can be used as a starting point for more complex requirements.

The 20th of April I was supposed to give the pgchameleon’s talk at the Pycon 9. However personal issues prevented me to come to Florence. This post is an explanation and an apology for the pycon 9 attendees and organisers.

Database administrators usually work behind the scenes, over the weekends and in antisocial hours. They strive to look after the database which is at the core of any business with little or no recognition.

The sad truth is that the DBA is one of the most obscure and one of the less appreciated roles within the IT organisations.

One of the things that distinguish PostgreSQL from other database systems is the way the dependencies between database objects are managed.

PostgreSQL do not allow any invalid object like views or functions. Therefore any action that can invalidate dependent objects results in an error or it’s propagated to the dependent objects.

The mechanism could be confusing at first sight. However the implementation is brilliant and gives great flexibility.

When in February I received the email with the news that my talk was accepted at the pgcon it took me some time, and several espresso coffee, to realise that I wasn’t dreaming. The pgcon email reached me few days after the same talk was accepted at the pycon nove, the Italy’s nationwide Python conference. The Italian Pycon and the Pgcon are great conferences with amazing speakers and fantastic topics. The sole idea of giving my small contribution it makes me proud and a little scared, because I never talked to an audience composed mostly by fine developers.