[Sqlalchemy-tickets] Issue #3698: Error in Directed Graph Documentation (zzzeek/sqlalchemy)

[John M. <iss...@bi...>]

New issue 3698: Error in Directed Graph Documentation
https://bitbucket.org/zzzeek/sqlalchemy/issues/3698/error-in-directed-graph-documentation

John Mercouris:

If you look in the examples, the documentation mentions that you may setup directed graphs:
http://docs.sqlalchemy.org/en/rel_1_0/orm/examples.html#module-examples.graphs

The code for the directed graph can be found here:
http://docs.sqlalchemy.org/en/rel_1_0/_modules/examples/graphs/directed_graph.html

Unfortunately the code for the directed graph is actually for an undirected graph
(directed vs undirected graph) http://www.differencebetween.com/wp-content/uploads/2011/05/DifferenceBetween_Directed_UnDirected_Graphs1.jpg

The reason it is a directed graph is because you may not add a relationship from n1->n2 as well as from n2->n1. The program will crash and complain that there is a duplicate entry. 

For your convenience I have modified the program to show an example of a directed graph:
(http://pastebin.com/xJDPdvYJ) - also attached to this issue. Also attached is the database generated from running the file.

You can run the program to demonstrate it for yourself, thank you for your time.