RDF::Query - A SPARQL/RDQL implementation for RDF::Redland and RDF::Core

RDF::Query allows RDQL and SPARQL queries to be run against an RDF model, returning rows of matching results.

Requirements

To install RDF::Query you'll need the following perl modules installed:

• Parse::RecDescent
• LWP::Simple
• RDF::Core or RDF::Redland

Installing RDF::Query

To install, run:

Version History

Version 1.024 (2005-06-02)

• Added missing SPARQL OFFSET grammar rules.
• Added XML Results support for graph and boolean queries (DESCRIBE, CONSTRUCT, ASK).
• Fixed major bugs in RDF::Core bridge:
  • - Bridge wasn't using passed model.
  • - Literal construction was broken.
  • - Blank node construction was broken when no identifier was specified.
• Stream::bindings_count now returns the right number even if there is no data.
• XML Result format now works with RDF::Core models.
• The Model bridge object is now passed to the Stream constructor.
• Internal code now uses the variables method.
• Removed redundant code from ORDER BY/LIMIT/OFFSET handling.
• Removed unused count method.
• Removed unused delegating AUTOLOAD.
• Removed unused parse_files method.
• Removed usused add_file method.
• Removed duplicate net test file.
• Added test file for local file-based SPARQL 'FROM' queries.
• Added test file for SPARQL Result Forms (LIMIT, ORDER BY, OFFSET, DISTINCT).
• Added test file for SPARQL Protocol for RDF (XML Results).
• Added new tests based on Devel::Cover results.
• Some test files now run against both Redland and RDF::Core:
  • - 00-simple.t
  • - 03-coverage.t
  • - 10-sparql_protocol.t
• All debugging is now centrally located in the _debug method.
• Moved Stream class to lib/RDF/Query/Stream.pm.
• Fixed tests that broke with previous fix to CONSTRUCT queries.
• Fixed tests that broke with previous change to ASK query results.

Version 1.021 (2005-06-01)

• Added SPARQL UNION support.
• Broke OPTIONAL handling code off into a seperate method.
• Added new debugging code to trace errors in the twisty web of closures.

Version 1.020 (2005-05-18)

• Added support for SPARQL OPTIONAL graph patterns.
• Calling bindings_count on a stream now returns 0 with no data.
• Added Stream methods:
  • is_bindings
  • binding_name
  • binding_values
  • binding_names
• Added as_xml method to Stream class for XML Binding Results format.

Version 1.016 (2005-05-08)

• Added initial support for SPARQL ASK, DESCRIBE and CONSTRUCT queries.
  • Added new test files for new query types.
• Added methods to bridge classes for creating statements and blank nodes.
• Added as_string method to bridge classes for getting string versions of nodes.
• Broke out triple fixup code into fixup_triple_bridge_variables().
• Updated FILTER test to use new Geo::Distance API.

Version 1.015 (2005-05-03)

• Fixes to the arguments passed to FILTERs.
• Filter tests now show example of two custom filters:
  • Transitive subClassOf testing.
  • Logical comparison operators (range testing lat/lon values).
• Added literal_value, uri_value, and blank_identifier methods to bridges.
• Redland bridge now calls sources/arcs/targets when only one field is missing.
• Fixes to stream code. Iterators are now destroyed in a timely manner.
  • Complex queries no longer max out mysql connections under Redland.
• Cleaned up node sorting code.
  • Removed dependency on Sort::Naturally.
  • Added new node sorting function ncmp().
• check_constraints now calls ncmp() for logical comparisons.
• Added get_value method to make bridge calls and return a scalar value.
• Fixed node creation in Redland bridge.
• Moved DISTINCT handling code to occur before LIMITing.
• Added variables method to retrieve bound variable names.
• Added binding_count and get_all methods to streams.
• get_statments bridge methods now return RDF::Query::Stream objects.

Version 1.014 (2005-04-26)

• Made FILTERs work in SPARQL.
• Added initial SPARQL support for custom function constraints.
• SPARQL variables may now begin with the '$' sigil.
• Added direction support for ORDER BY (ascending/descending).
• Added 'next', 'current', and 'end' to Stream API.

Version 1.012 (2005-04-24)

• Stream objects now handle being constructed with an undef coderef.
• Streams are now objects usinig the Redland QueryResult API.
• RDF namespace is now always available in queries.
• row() now uses a stream when calling execute().
• Added ORDER BY support to RDQL parser.
• SPARQL constraints now properly use the 'FILTER' keyword.
• SPARQL constraints can now use '&&' as an operator.
• SPARQL namespace declaration is now optional.
• Updated tests.

Version 1.010 (2005-04-21)

• execute now returns an iterator
• Added core support for DISTINCT, LIMIT, OFFSET
• Added initial core support for ORDER BY (only works on one column right now)
• Broke out the query parser into it's own RDQL class
• Added initial support for a SPARQL parser
  • Added support for blank nodes
  • Added lots of syntactic sugar (with blank nodes, multiple predicates and objects)
  • Added SPARQL support for DISTINCT and ORDER BY
• Moved model-specific code into RDF::Query::Model::*
• Moving over to redland's query API (pass in the model when query is executed)

Copyright

Copyright © 2005 Gregory Williams. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.