pgenv is a shell script that allows you to quickly manage multiple PostgreSQL installations within the same host. It reminds somehow
perlbrew (for Perl 5) and systems like that. In this post I briefly show how to use
pgenv as well as I explain which changes I made to it.
Rules are a powerful mechanism by which PostgreSQL allows a statement to be transformed into another. And PostgreSQL itself does use rules in order to make your life easier.