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SPARQL for faceted browsing (was: Re: Owning URIs (Was: Yet Another LOD cloud browser))

From: Andreas Harth <andreas@harth.org>
Date: Sun, 31 May 2009 21:09:19 +0200
Message-ID: <4A22D5DF.4010000@harth.org>
To: Dan Brickley <danbri@danbri.org>
CC: Kingsley Idehen <kidehen@openlinksw.com>, Daniel Schwabe <dschwabe@inf.puc-rio.br>, David Huynh <dfhuynh@alum.mit.edu>, Linked Data community <public-lod@w3.org>, semantic-web@w3.org
Hi,

Dan Brickley wrote:
> Basic idea in a nutshell is that SPARQL is great for data access, but 
> there may be additional query-oriented data structures worth spec'ing 
> based around the set-oriented navigation very nicely articulated by 
> David Huynh in the Parallax screencast. And that if such a structure 
> could be exchanged between systems we could hope that the navigational 
> paradigm it supports could be found in various concrete UIs, and that 
> the results of exploring data this way could become useful and 
> standard artifacts in the public Web, rather than just bookmarks 
> within some specific system.

there's at least two issues with using standard SPARQL endpoints
in a faceted browsing system (as far as I can see from my experiements
with SWSE and VisiNav):

* A lot of end-user systems for RDF data navigation offer keyword
search, which is not in standard SPARQL.  Emulating fulltext search
with SPARQL regex's seems suboptimal.  Using endpoint-specific
FILTERs or magic predicates requires adaptations depending on
the RDF store used, and might be tricky when you want to mix
SPARQL endpoints from different vendors.

* Ranking is essential for systems offering navigation over web data.
LIMIT is ok to improve performance by keeping the result size small,
but query processors will then return arbitrary results that wouldn't
satisfy end users who expect relevant (i.e. ranked) results.

Regards,
Andreas.
Received on Sunday, 31 May 2009 19:10:05 GMT

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