From: Frank van Harmelen (Frank.van.Harmelen@cs.vu.nl)
Date: 09/25/01
After a question from me, Mike pointed out a misconception on my part: DAMLDB is not a storage device for DAML+OIL, but is an RDF store (not aimed at supporting any of the DAML+OIL primitives). As Mike explained: the name reflects the project, not the language. So I have to redraw my map: STORAGE DEVICES - RDF: There are already quite a number of RDF storage devices out there. I will not bother to repeat them, see the RDF resource page at [4] (which includes Frodo by Stefan and others), plus the recently announced DAML DB by Mike at [6] - RDF Schema: I am aware of only one storage device that is tailored towards RDF Schema, namely Sesame, at [4] - DAML+OIL: no known storage devices yet (or should we count FaCT as such?). CONCLUSION: much work on RDF storage, only one (!) attempt at RDF Schema storage, no (!!) work yet on DAML+OIL storage (besides FaCT, which predates DAML+OIL). The rest of my map remains unchanged, and follows for completeness again. Frank. ---- QUERY LANGUAGES - DQL: query-language for DAML+OIL, proposed by Richard Fikes et al in [1] - RQL: query-language for RDF Schema, proposed by the people from Heraklion [2] - RDQL: query-language for RDF, from the folks at HP Labs Bristol [3] Remark 1: By saying that "X is a query language for Y", I mean that both the syntax and the semantics of X provide facilities to deal with modelling primitives from Y. So, in a trivial way, any RDF query language is also an RDF Schema query language, but only in a trivial way. Any propoer RDF Schema query language should support (for instance) querying the subClassOf relation, taking into account its transitivity. Remark 2: Since there are such clear containment relations between the language RDF, RDF Schema, DAML+OIL, I would very much hope that it will turn out to be possible to reflect this stacking of languages in the corresponding query languages. Remark 3: In general, the storage devices are independent from a particular query language, but of course a storage device for language X will most likely have support for a query language for X. Eg: Sesame stores RDF Schema, and supports RQL, but support for DQL (or RDQL) could well be built on top of the same storage device. Frank. --- [1] DQL proposal: http://www.daml.org/listarchive/joint-committee/0572.html [2] RQL tutorial: http://sesame.aidministrator.nl/doc/rql-babysteps.html [3] RDQL home page: http://www-uk.hpl.hp.com/people/afs/RDQL/ [4] RDF storage tools: http://www.ilrt.bris.ac.uk/discovery/rdf/resources/ [5] Sesame home page: http://sesame.aidministrator.nl [6] DAMLDB page: http://www.daml.org/2001/09/damldb/
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