- From: Seaborne, Andy <andy.seaborne@hp.com>
- Date: Thu, 25 Jun 2009 13:23:06 +0000
- To: SPARQL Working Group <public-rdf-dawg@w3.org>
The text for "time-permitting" features (inc Birte's suggestion) is good for me for FPWD. Andy > -----Original Message----- > From: public-rdf-dawg-request@w3.org [mailto:public-rdf-dawg- > request@w3.org] On Behalf Of Lee Feigenbaum > Sent: 25 June 2009 13:36 > To: Birte Glimm > Cc: SPARQL Working Group > Subject: Re: Potential text for time-permitting features in F&R > > Birte, thanks. Sounds good to me. > > Lee > > Birte Glimm wrote: > > Lee, > > thanks for the work. I would suggest to rephrase OWL dialects into > > profiles because that is the official name used in the OWL 2 spec (I > > guess that is what you mean by dialects) and I would like to mention > > direct semantics here because the RDF semantics of OWL does not really > > need a different entailment regime as I understand it, e.g.: > > > > [...] Time-permitting, the SPARQL WG will use the existing framework > > to define the semantics of SPARQL queries for one or more of these > > entailment frameworks: > > + OWL 2 with Direct Semantics including OWL 2 profiles > > + RDF Schema > > + RIF rule sets > > > > Birte > > > > 2009/6/25 Lee Feigenbaum <lee@thefigtrees.net>: > >> This is to discharge my action at > >> http://www.w3.org/2009/sparql/track/actions/49 > >> > >> The goal here is to have enough text that explains what the time > permitting > >> features are in a way that: > >> > >> 1) is comprehensive enough to help us build out phase II charter > >> 2) will be re-usable / extendable in future versions of the F&R > document > >> > >> To this end, I've tried to do a "Motivation" and brief "Description" > for > >> each. > >> > >> Please comment on this, _especially_ if you are not comfortable with > any of > >> this for the FPWD. We are _not_ going to spend time on this specific > text on > >> Tuesday before deciding to publish a first public working draft unless > there > >> are concerns that we have not managed to work out between now and then > on > >> the mailing list. > >> > >> Kjetil or Alex, can you please work this into the editor's draft? > >> > >> Also - please note that we may need to refine the description of common > >> functions that is a time-permitting function before publishing the > phase ii > >> charter, as per ISSUE-2 > (http://www.w3.org/2009/sparql/tracker/issues/2). We > >> can do this following publication of FPWD of F&R. > >> > >> > >> ~~BGP extensions for entailment regimes~~ > >> > >> -Motivation- > >> > >> Many software systems that support entailment regimes such as OWL > dialects > >> and RDF Schema extend the semantics of SPARQL Basic Graph Pattern > matching > >> to apply to entailments other than simple entailment. The formal > semantics > >> of these SPARQL/Query extensions are not standardized, and query > writers > >> cannot currently be guaranteed interoperable behavior when working with > >> multiple query engines that extend SPARQL with the same entailment > regime.. > >> > >> -Description- > >> > >> SPARQL/Query 1.0 defines a mechanism to adapt SPARQL to entailment > regimes > >> beyond simple entailment by providing necessary conditions on re- > defining > >> the meaning of SPARQL Basic Graph Pattern matching. Time-permitting, > the > >> SPARQL WG will use the existing framework to define the semantics of > SPARQL > >> queries for one or more of these entailment frameworks: > >> + OWL dialects, including OWL DL > >> + RDF Schema > >> + RIF rule sets > >> > >> > >> ~~Property paths~~ > >> > >> -Motivation- > >> > >> Many classes of query over RDF graphs require searching data structures > that > >> are hierarchical and involve arbitrary-length paths through the graphs. > >> Examples include: > >> > >> * Retrieving all the elements of an RDF collection (structured as a > linked > >> list) > >> * Retrieve all of the names of people linked to me transitively via > the > >> ex:mother and ex:father relationships (i.e. all my known ancestors) > >> * What are all of the direct and indirect superclasses of a given > >> owl:Class? > >> > >> -Description- > >> > >> SPARQL/Query 1.0 can express queries over fixed-length paths within RDF > >> graphs. SPARQL/Query 1.0 can also express queries over arbitrary but > >> bounded-length paths via repeated UNION constructs. SPARQL/Query 1.0 > cannot > >> express queries that require traversing hierarchical structures via > >> unbounded, arbitrary-length paths. > >> > >> Time-permitting, the SPARQL Working Group will define the syntax and > >> semantics of property paths, a mechanism for expressing arbitrary- > length > >> paths of predicates within SPARQL triple patterns. > >> > >> > >> ~~Basic Federated Query~~ > >> > >> -Motivation- > >> > >> SPARQL is a concise query language to retrieve and join information > from > >> multiple RDF graphs via a single query. In many cases, the different > RDF > >> graphs are stored behind distinct SPARQL endpoints. > >> > >> -Description- > >> > >> Federated query is the ability to take a query and provide solutions > based > >> on information from many different sources. It is a hard problem in its > most > >> general form and is the subject of continuing (and continuous) > research. A > >> building block is the ability to have one query be able to issue a > query on > >> another SPARQL endpoint during query execution. > >> > >> Time-permitting, the SPARQL Working Group will define the syntax and > >> semantics for handling a basic class of federated queries in which the > >> SPARQL endpoints to use in executing portions of the query are > explicitly > >> given by the query author. > >> > >> > >> ~~Commonly Used SPARQL Functions~~ > >> > >> -Motivation- > >> > >> Many SPARQL implementations support functions beyond those required by > the > >> SPARQL/Query 1.0 specification. There is little to no interoperability > >> between the names and semantics of these functions for common tasks > such as > >> string manipulation. > >> > >> -Description- > >> > >> Time-permitting, the SPARQL WG will define URIs and semantics for a set > of > >> functions commonly supported by existing SPARQL implementations. > >> > >> See Working Group issue: ISSUE-2 - > >> http://www.w3.org/2009/sparql/tracker/issues/2 > >> > >> > >> ~~Query language syntax~~ > >> > >> -Motivation- > >> > >> Certain limitations of the SPARQL/Query 1.0 language syntax cause > >> unnecessary barriers for learning and using SPARQL. > >> > >> -Description- > >> > >> Time-permitting, the SPARQL Working Group will consider extending > >> SPARQL/Query's syntax to include: > >> + Commas between variables and expressions within a SELECT list > >> + IN and BETWEEN operators to abbreviate disjunction and comparisons > within > >> FILTER expressions > >> > >> > >> Lee > >> > >> > > > > > >
Received on Thursday, 25 June 2009 13:24:22 UTC