Re: [ba-ohs-talk] new version of graph model paper posted
On Wed, 2002-04-17 at 10:17, Peter Jones wrote:
> Lee Iverson wrote:
> > I'm not sure I follow. What kinds of queries would lead to these
> > "bifurcations"? In a general sense, since equality of two nodes is
> > easy to determine, it is fairly simple to ensure that in any query
> > result multiple references to the same node get properly resolved.
>
> I was thinking of graph structures like the following:
>
> A--------------B1
> | |
> | |
> | |
> B2-------------C
>
> Where B1 and B2 are not identical nodes, but nonetheless contain the
> same value in respect of the particular
> property being queried for.
> So if I express my query as A-[B*]-C then some sort of decision has
> to be made about what the result should be: Two B's or two C's or what?.
> (One way would be to bin the idea of ordinary documents altogether and
> just have hyperdocuments.) (01)
So, your query is asking for configurations of the form:
A -> B* -> C (02)
As far as I see it, the query engine should return two results:
A -> B1 -> C
A -> B2 -> C
and care must be taken that both references to C are returned in such
a way that the client can easily determine that they resolve to
the same value. In XML this might be accomplished with something
like: (03)
<resultset>
<A>
<B1> <C name="c0"/> </B1>
<B2> <C href="#c0"/> </B2>
</A>
</resultset> (04)
Am I missing something? (05)
--
-------------------------------------------------------------------------------
Lee Iverson
leei@ece.ubc.ca Dept of ECE, 2356 Main Mall
http://www.ai.sri.com/~leei/ Vancouver BC Canada V6T 1Z4
Office: (604) 822-3381 (06)