- From: Andy Seaborne <andy.seaborne@talis.com>
- Date: Mon, 29 Mar 2010 15:54:18 +0100
- To: Eric Prud'hommeaux <eric@w3.org>
- CC: public-rdf-dawg@w3.org
Eric, This is great - I think we ought to include something in SPARQL 1.1 even if it's just the most basic SERVICE form because of time. It it the semantic *web* .... Andy On 27/03/2010 3:36 AM, Eric Prud'hommeaux wrote: > http://www.w3.org/2009/sparql/docs/fed/service > > take a look, help out, ... > -- > -ericP Specific comments: ** SERVICE "4.1 Definition of SERVICE" http://www.w3.org/2009/sparql/docs/fed/service#sparqlDefinition [[ The evaluation of service uses the SPARQL algebra union operator. ]] Elements of a group are usually join'ed together, not union'ed. Algebra example: Service(?s :p2 ?v2) ==> Service(<srvc> BGP(?s :p2 ?v2)) "with a query Q and no default or named graphs." I think that means no FROM or FROM NAMED - correct? ** BINDINGS This area is less clear to me - it's very useful to have something here but I'm not quite sure this is the right mechanism. It's another form of assignment. Is it the same as (the excessively verbose): { SELECT ("Alice" AS ?given) ("Anderson" AS ?family) (?mbox AS <mailto:alice@example.com>) } UNION { SELECT ("Bob" AS ?given) ("Robertson" AS ?family) (?mbox AS <mailto:eve@example.com>) } UION { ... } Probably better not to allow bNodes to be passed over the network. Suggest s/UNBOUND/_/ or something a liitle less heavy. "-" The definition of BINDING has UNDEF * BINDING and Update: This seems to overlap with INSERT DATA etc It is unrelated to federated query. The substutute operator might help in the definition: http://www.w3.org/2009/sparql/docs/query-1.1/rq25.xml#defn_substitute Result are then a union of substitute for each binding row. This is similar to the bind-join proposed by the IBM Garlic project. It allows for the bINDINGs to be streamed in parallel with results coming back. (this way the results of sending one BINDING at a time and sending all BINDINGS at once are the same). ** MIME Type Doesn't the query often go in ?query= which isn't MIME typed. Andy
Received on Monday, 29 March 2010 14:54:54 UTC