Re: Limits of SQL

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
>