Re: Limits of SQL

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
>
>
>
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     Regards,
         Oleg
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Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
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