You mean, you want to be able to say something like: select isConnected(a,b) and get back a true/false, or maybe the path? That seems quite doable in SQL, assuming you either store those results and simply use sql to retrieve them, or use a stored proc to compute the result each time. On Thu, 2 Jun 2005, Joachim Zobel wrote: > Hi. > > I am looking for a way to write a SELECT that finds connectivity > components of a graph or at least for one that given two nodes > determines if there is a path between them. It seems that this is not > possible, no matter what graph representation I choose. Which constructs > from set theory are missing in SQL? Set of all subsets is one I am > missing, or can it be done somehow? > > Is anybody else thinking about the limits of SQL? As often I am probably > not the first to ask these questions. Any pointers? > > Sincerely, > Joachim > > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: Have you searched our list archives? > > http://archives.postgresql.org > ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly
