> A --> B --> C > \ > \--> D --> E You've drawn a tree, but your comments indicate that you want something more general.
If you can restrict yourself to trees, you can probably use nested sets (invented by Joe Celko). These are fairly simple to manipulate. A Google search will turn up articles explaining the method. If you must have a more general graph, you'll probably have to store all the paths you're interested in, e.g., A/B A/B/C A/B/D A/B/D/E If you're interested in paths that don't start at the root, you'll need also B/C B/D B/D/E D/E If you add an arc directly from A to E, you'll need A/E. You could then get all the paths from A to E by searching for Path LIKE 'A%E'. In this case, you'll probably want to get all the paths you're interested in and then analyze and manipulate them in your host language. Things would be much simpler if you could limit yourself to trees modeled as nested sets. Regards
