- From: Wolfgang Nejdl <nejdl@kbs.uni-hannover.de>
- Date: Thu, 31 Jan 2002 20:52:12 +0100
- To: Libby Miller <Libby.Miller@bristol.ac.uk>
- cc: www-rdf-rules@w3.org, gt77@gmx.at
> > I just sent this reply to the rdf interest group list: I thought it > might be worth posting it here as well, in case I've missed out lots of > systems or got the details wrong. > Edutella (edutella.jxta.org) includes a Query Exchange Language based on Datalog semantics, called RDF-QEL-i (it's actually a family of languages, but with one common semantics). It is described in a WWW'11 paper (see http://edutella.jxta.org/reports/edutella-whitepaper.pdf for the preliminary version). cheers, Wolfgang > cheers, > > Libby > > > On Thu, 31 Jan 2002 gt77@gmx.at wrote: > > > Hi! > > > > I´m 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/ > > -- Wolfgang Nejdl
Received on Thursday, 31 January 2002 14:53:05 UTC