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Re: API for querying a set of RDF graphs?

From: Benja Fallenstein <b.fallenstein@gmx.de>
Date: Wed, 19 Mar 2003 08:57:23 +0100
Message-ID: <3E7822E3.6070700@gmx.de>
To: "LYNN,JAMES (HP-USA,ex1)" <james.lynn@hp.com>
CC: rdf-i <www-rdf-interest@w3.org>

Dear James,

LYNN,JAMES (HP-USA,ex1) wrote:
> You may want to take a look at Jena (and the new version Jena 2).
> http://www.hpl.hp.com/semweb/index.htm
> You can get a quick look at the current query capabilities from the
> tutorial. Look at the section on RDQL.
> http://www.hpl.hp.com/semweb/doc/tutorial/index.html

I know about Jena and counted it among the query-a-single-graph APIs. In 
fact, the examples given in the tutorial seem to support this 
interpretation-- they seem to be queries on a single graph, and they do 
not seem to report which graph results came from.

If I am understanding the docs wrong here, can you explain where I can 
find details?

Thank you,
- Benja

> -----Original Message-----
> From: Benja Fallenstein [mailto:b.fallenstein@gmx.de]
> Sent: Tuesday, March 18, 2003 5:36 PM
> To: rdf-i
> Subject: API for querying a set of RDF graphs?
> Hi all,
> I am developing a system that stores a number of RDF graphs, possibly 
> downloaded from different places, and I need to run queries over that 
> data. (The store may also be the virtual collection of all graphs 
> available on a p2p network.) I may not trust all graphs in my store for 
> all purposes. I'm imagining an API that would let me run simple queries 
> over all the graphs (individually; I don't need to solve the harder 
> problem where two graphs taken together answer the query), and return 
> results together with a tag saying which graph a result came from. Then 
> I could decide which of the graphs is applicable, meaning a) trustworthy 
> and b) a current, not an obsoleted version.
> I've been doing some work on this, but it occurs to me that such an API 
> would be useful for the Semantic Web in general-- querying a search 
> engine or similar service for published graphs that answer some query. 
> So I was wondering, do APIs for this purpose exist-- especially in Java? 
> The APIs I've looked at so far seem to be geared at querying a single 
> graph (which may be the virtual union of other graphs, but such an API 
> would not provide me with information about which graph a result came 
> from, making it impossible to evaluate which results can be trusted and 
> which can't).
> So, which APIs like this are out there?
> Thanks for your help,
> - Benja Fallenstein
Received on Wednesday, 19 March 2003 02:57:45 UTC

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