Those are my two all times favorite Open Source Software. Or Free Software in the GNU sense of the world, as both the BSD and the GPL are labeled free there. Even if I prefer the The Debian Free Software Guidelines as a global definition and the WTFPL license. But that's a digression.
I think that Emacs and PostgreSQL do share a lot in common. I'd begin with the documentation, which quality is amazing for both projects. Then of course the extensibility with Emacs Lisp on the one hand and catalog-driven operations on the other hand. Whether you're extending Emacs or PostgreSQL you'll find that it's pretty easy to tweak the system while it's running. The other comparison points are less important, like the fact the both the systems get about the same uptime on my laptop (currently 13 days, 23 hours, 57 minutes, 10 seconds).
So of course I'm using
Emacs to edit
.sql files, including stored
procedures. And it so happens that
line numbering in plpgsql is not as
straightforward as one would naively think, to the point that we'd like to
have better tool support there. So I've extended Emacs
linum-mode minor mode
to also display the line numbers as computed per PostgreSQL, and here's what
it looks like:
Now, here's also the source code, pgsql-linum-format. Hope you'll enjoy!