SPARQL 1.1 Status

1.1
What’s coming and what might be coming?
May, 2010
Latest at http://www.slideshare.net/LeeFeigenbaum/sparql2-status
Lee Feigenbaum, Co-chair, SPARQL Working Group
lee@thefigtrees.net

Disclaimer
The SPARQL Working Group has not yet decided many of the technical questions surveyed in these slides. All examples are subject to change; please do not construe them as indicators or endorsements of specific technical designs/decisions.
All opinions are Lee Feigenbaum’s alone.

Naming
SPARQL 1.1 is the collective name of the work produced by the current SPARQL Working Group. The actual components being worked on are known as:SPARQL 1.1 QuerySPARQL 1.1 Update
SPARQL 1.1 Service Description
…

Where are we now?
Today
August 2010
March 2009
???
Last Call and beyond of core SPARQL specifications
July 2009
FPWD of SPARQL New Features and Rationales document
October 2009
FPWD of core SPARQL specifications

Overview

Projected Expressions
Select expressions other than variables (literals, functions on literals and variables, etc.)
SELECT (?price* ?qty AS ?total_price)
WHERE {
…
}

Aggregates
À la SQL aggregates (MIN, MAX, COUNT, AVG, SUM etc.)
Issues around:
Aggregates and error values
Grouping by expressions
SELECT (MIN(?price) AS ?min_price)…
WHERE { … }
GROUP BY ?item

Subqueries
Nested queries allow multiple queries to be combined into one.
SELECT ?article ?authorWHERE { ?article ex:author ?author . { SELECT ?article WHERE { … ?article … } ORDER BY … LIMIT … }}

Negation
Supplant the mystifying OPTIONAL/!bound method of negation with a dedicated construct
Issues around:
Filter semantics vs. set-difference semantics
Graph pattern operators vs. filter functions
SELECT … WHERE { ?person a foaf:Person .
MINUS{
?person foaf:mbox ?email
}
}

Service Description
A standard discovery mechanism and vocabulary for describing the capabilities, extensions, data sets, and more for a SPARQL endpoint
Discovery. How can a client find the RDF that describes a SPARQL endpoint at a particular URI?
Description. What predicates, classes, values, etc. should a client expect to find (and be able to query) once it locates a service description?

Update Language
Based on the SPARQL Update member submission
Batch insert & delete
Insert & delete based on triple patterns
Graph management (creation, removal)
Issues around:
Defining a formal model for update
Graph stores vs. RDF data sets
Return codes

Update Protocol
The ability to issue SPARQL/Update language statements via a standard protocol (e.g. via HTTP POST)
Issues around:
Security
Response HTTP codes

HTTP RDF update (RESTful)
Where appropriate, map HTTP requests to SPARQL/Update operations
DELETE /foo/g1 …-> DELETE DATA FROM ex:g1 …
Issues around:
Which mappings to include?
Are graphs information resources?

Property Paths
Support arbitrary-length predicate paths in triple patterns – “regular expressions” on predicates?
Query hierarchical structures such as RDF collections
Issues around:
Duplicates and cycles in paths
Negated path segments
SELECT … WHERE { ?person foaf:knows+ ?network .
}

Basic Federated Query
Initial scaffolding for authoring federated SPARQL queries
Add a keyword to explicitly target portions of a query to specific endpoints
Issues around:
SERVICE and variables?
Is federated query its own document?
SELECT … WHERE { … SERVICE ex:books {
…
}
}

Entailment Regime Semantics
SPARQL/Query 1.0 defines a mechanism to extend SPARQL semantics for additional entailment regimes
Use this mechanism to define the semantics of SPARQL queries for:
RDF Schema
OWL fragments
RIF rule sets
…

Common Functions
Extend the set of functions that SPARQL engines must support to include some of…
Common string functions (e.g. substr)
Common date/time/datetime functions
Logical functions (COALESCE, IF, …?)
Limited discussion to date about which functions to include

Get Involved
Join.
Email team-sparql-chairs@w3.org
Follow.
WG materials at http://www.w3.org/2009/sparql/wiki/
Comment.
Public feedback at public-rdf-dawg-comments@w3.org
Use.
Discuss SPARQL at public-sparql-dev@w3.org

SPARQL 1.1 Status

by LeeFeigenbaum on Sep 08, 2009

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SPARQL 1.1 Status — Presentation Transcript