I'm not sure if it's relevant to your question http://www-2.cs.cmu.edu/~cache/pg_graph/
pg_graph provides a way of handling graph-based data structures within the relational database PostgreSQL. In particular, it provides a convenient means of inserting graphs as BLOB-like objects in the RDBMS. Primarily, however, it provides a mechanism for indexing the graphs to provide efficient means to perform nearest-neighbor queries over collections of graphs.
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
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