Re: a map to acronym space on query languages & storage devices

From: Frank van Harmelen (
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:


- 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.



- 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. 


[1] DQL proposal:
[2] RQL tutorial:
[3] RDQL home page:
[4] RDF storage tools:
[5] Sesame home page:
[6] DAMLDB page:

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