a couple of weeks ago you developed some code to convert a pair of
tables to a graphviz digraph and you wrote a very useful Worg page
about
it:
http://article.gmane.org/gmane.emacs.orgmode/74280
http://orgmode.org/worg/org-tutorials/org-dot-diagrams.html
I just wanted to say two things about it:
1. if the typical use case is to use the code with #+call:, it would be
more helpful to delete the #+header: line in the source code in the
Worg page. This header line presumes that the particular tables in
your first example exist. Deleting this line means that the code
can only be used via a #+call statement but I think this is more
logical.