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(unknown charset) Re: RDF query language

From: (unknown charset) Libby Miller <Libby.Miller@bristol.ac.uk>
Date: Thu, 31 Jan 2002 13:41:52 +0000 (GMT)
To: (unknown charset) gt77@gmx.at
cc: (unknown charset) www-rdf-interest@w3.org
Message-ID: <Pine.GSO.4.44.0201311255000.2531-100000@mail.ilrt.bris.ac.uk>


On Thu, 31 Jan 2002 gt77@gmx.at wrote:

> Hi!
>
> Im going to write my diploma thesis about evaluating different RDF-query
> languages.  Therefore I would like to know, if someone can give me an brief
> overview (or interesting links) about the most important and powerful query
> languages (like redland or jena), which I should include in my thesis. Many
> thanks in advance!
>
> Gerald
>
> --
> GMX - Die Kommunikationsplattform im Internet.
> http://www.gmx.net
>
>

Hi Gerald. I think other people might have a better summary than I do,
but I have a bunch of notes from something else I've been doing about a
simple query language that I've been working on with Andy Seaborne
called SquishQL, which is why I'm interested (see notes below, which
are not comprehensive). You might also like to try
www-rdf-rules@w3.org, which is the mailing list
for rdf rules and query. Look at its archive:
http://lists.w3.org/Archives/Public/www-rdf-rules/

I'm not sure what you mean by 'important and powerful' query langauges.
There are a number of RDF management systems out there which include
large databases and use query languages. Some don't have query
languages, like Redland, but are still very useful and scalable. I've
been using a simple RDF query language, because it meets my
requirements.

Hope this helps anyway.

Libby


Some RDF query languages have been in in use for several years.
R.V. Guha's rdfDB query language [1] was the first of these (as far as I
can tell) and is the basis for SquishQL. It is a simple graph-matching
query language designed for use with the rdfDB system. It differs
slighty syntactically from SquishQL and also does not contain the
constraints on the variables used by SquishQL. It returns results as a
table. rdfDB is written in C, I think.

Algae [2] is another early query language for RDF, written by Eric
Prud'hommeaux of W3C in Perl. It uses an S-expression syntax to do graph
matching. It can handle contraints of some kinds, I think. It is used to
power the W3C's Annotea annotations system [3], and other software at
the W3C. It's written in Perl, and can be used with an SQL database.

RQL [4] has a very different syntax, based on OQL, but can perform
similar sorts of queries, with the added power of syntactic support for
transitive closure on RDF subclass and subproperty. It is used by the
Sesame system [5].

SquishQL is one of a number of query languages syntactically similar to
rdfDB's. These include one by Geoff Chappell for RDFGateway [6], and one
by David Allsopp [7]. RDFGateway QL is interesting because it is a
simple query language over a database that can understand and process
rules. David Allsopp's QL has syntactic support for regex path
expressions.

There are a number of other query languages being created at the moment,
including a DAML QL [8], Triple [9], RDFPath [10]. There a number of
papers at QL98 that you might find helpful, including one by R.V.Guha et
al [11] which heavily influenced SquishQL. It might also be worth
looking at the notes from the RDF Query birds of a feather meeting last
August [12].

I've been working on SquishQL, formerlly Squish[13], a simple SQL-ish
RDF query language for a couple of years with Dan Brickley and also with
Andy Seaborne of HP, who has done an implementation called RDQL[14] for
Jena. I have an implementation called Inkling[15].

[1] http://web1.guha.com/rdfdb/query.html http://guha.com/rdfdb/

[2] http://www.w3.org/2001/Talks/0505-perl-RDF-lib/slide8-0.html

http://ilrt.org/discovery/2001/08/rdfquery-bof/

http://www.w3.org/2001/Annotea/User/Protocol.html

http://www.w3.org/1999/02/26-modules/User/Algae-HOWTO.html (BNF)

http://www10.org/cdrom/papers/488/

[3] http://www.w3.org/2001/Annotea/

[4] A paper on RQL
       http://www.ics.forth.gr/proj/isst/RDF/RQL/rql.html
       BNF
       http://139.91.183.30:9090/RDF/RQL/bnf.html
       RQL tutorial
       http://sesame.aidministrator.nl/

[5]
       http://sesame.aidministrator.nl/


[6]
http://www.intellidimension.com/RDFGateway/Docs/rdfqlgettingstarted.asp

[7] http://ilrt.org/discovery/2001/08/rdfquery-bof/
          http://www.semanticweb.org/SWWS/program/full/paper10.pdf

[8] http://www.ai.sri.com/daml/notes/HW2/SemanticWeb/paper.html
       http://www.daml.org/listarchive/joint-committee/0572.html

http://lists.w3.org/Archives/Public/www-archive/2001Sep/0016.html
       http://www.w3.org/2000/10/swap/test/dpoq22Aug/query-answer.daml
       http://www.daml.org/listarchive/joint-committee/0598.html

- probably more by now...

[9]

http://www.daml.org/listarchive/joint-committee/0673.html
          http://www.dfki.uni-kl.de/frodo/triple/

[10] http://groups.yahoo.com/group/rdfpath/


[11] http://www.w3.org/TandS/QL/QL98/pp/enabling.html

[12] http://ilrt.org/discovery/2001/08/rdfquery-bof/

[13] http://ilrt.org/discovery/2000/10/swsql/

[14] http://hpl.hp.com/semweb/

[15] http://swordfish.rdfweb.org/rdfquery/
Received on Thursday, 31 January 2002 08:44:14 GMT

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