- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Thu, 15 Jul 2004 16:29:21 -0400
- To: "Jeff Pollock" <Jeff.Pollock@networkinference.com>, <public-rdf-dawg@w3.org>
- Message-Id: <p06110400bd1c94ebefa9@[10.0.0.11]>
At 11:24 -0700 7/15/04, Jeff Pollock wrote: All- As everyone in attendance at the DAWG FTF is aware, the Network Inference position is that XQuery represents an ideal concrete syntax to facilitate more widespread and rapid adoption of the semantic web stack, beyond just RDF. In support of the charter, NI proposes that the discussion of a strawman query language is not inherently at odds with an eventual XQuery based concrete syntax. The DAWG charter contemplates three stages of specification evolution; (1) strawman language, (2) abstract syntax and (3) concrete syntax. Network Inference does not perceive BRQL, RDQL, or N3QL proposals as necessarily excluding an eventual outcome that is consistent with an XQuery concrete syntax. The DAWG charter also clearly states that: "The RDF DAWG should aim to maximize W3C technology re-use, while also taking account of differences between the RDF graph data model and the XQuery data model" - thereby supporting our objective that XQuery be an integral part of an end-user's interface with the eventual DAWG language recommendation. Therefore, NI proposes that a new requirement be considered by this group: "The query language shall have an XQuery compatible concrete language syntax." Network Inference has formalized the rationale for this requirement in the attached document that explores the facets of why this is important to us, and ultimately as to why it should be important to the W3C community at large. Comments, stones, or support are welcome. Kind Regards, -Jeff- Jeff - thanks for this document - it seems helpful - since I'm not there I cannot really follow the arguments, but I must admit I find this document confuses me more, not less. some questions; you say 20+ vendors support some sort of Xquery. best I can tell, however, most of those assume you are using a XML DB. Some 200+ vendors seems to support SQL, including MS access and Oracle and lots of the other "big kids" -- and they don't assume an XML DB. I'm assuming that in most of the applications people will build, the RDF will live in a triple store (like Tucana builds, for example) and thus they won't be in an XML DB per se -- so would Xquery really speed up adoption or slow it down? SQL is also taught in every CS dept in America (I can't speak for outside the US, although I did sit in on some DB lectures using SQL in the UK, so it's at least taught there as well). There are also many packages (like JDBC) that provide APIs for working with SQL-like langauges, wouldn't that be an argument for that sort of syntax? You show RDFS/OWL/Rule query langauges as somehow being more easy in Xquery, but again I think that is because you are assuming these things will be kept in their RDF/XML documents, or in APIs that respect the "boundaries" of those. I already see many applications moving towards multiontologies w/linking, and that seems to me to argue that we simply don't know yet which of these models are better. Let me be clear, I'm not opposed to an XQuery-based model, and I am not really a big fan of SQL, but I see a lot of the DB community folks (Several papers at TODS and VLDB workshops, in fact) that are arguing in favor of RDF DBs precisely because they can handle algebras similar to relational, and because they can scale well in the way RDBMS do (and they're worried about the scaling of XML DBs, esp in the VLDB world) So I would be okay with the requirement you propose assuming one - this can't be the ONLY concrete language syntax - I would expect that we could do something like we did in the OWL case, where we had an abstract syntax with two surface realizations (XML and RDF/XML) - this guaranteed that interoperability between the XML and RDF version was possible, as they were provably mappable one to the other two - I would like to see some evidence of the scalability of these Xquery things -- this is not meant to be hostile, I'm just a lot more comfortable with the SQL world (where I have over 25 years of experience) than with the newer Xquery world, so I simply don't know what Xquery Algebras and calculi look like, and thus I don't have an inuitive feel for their scalability, etc. I suspect Tucana and others would be willing to make their DB query times public for some set of queries - is there any way we could run a comparison on some large scale test cases or someting like that (I looked on the NI site for some examples, but there is nothing publicly available) Please, let me be clear -- rereading this it looks like I'm being negative, but I don't mean to be -- I'm actually trying to understand the situation and see whether the positions we seem to hold are compatible or not -- I certainly have not predecided this issue -JH p.s. And if you think I may be somehow hostile to NI, please talk to Jack Berkowitz and get him to tell you how supportive I was during the Web Ont work. -- Professor James Hendler http://www.cs.umd.edu/users/hendler Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) Univ of Maryland, College Park, MD 20742 240-277-3388 (Cell)
Received on Thursday, 15 July 2004 16:29:56 UTC