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• 10/08/2009: D2RQ Engine V0.7 and D2R Server V0.7 have been released. The new releases provides several bugfixes, better dump performance, several new features as well as new optimizations that must be enabled via D2R Server's --fast switch or using d2rq:useAllOptimizations.
• 19/02/2009: D2RQ Engine V0.6 and D2R Server V0.6 have been released. The new releases provide significantly improved performance (upto factor 7 in the BSBM benchmark) thanks to improved rewriting of SPARQL statements into SQL, as well as a new ARQ-based QueryEngine. The D2RQ release improves memory usage and fixes various bugs. In addition to MySQL it has also been sucessfully tested with Oracle. The new D2R Server release features support for dereferencing vocabulary URIs and for publishing mappings between different vocabularies.
• 26/01/2009: The W3C RDB2RDF Incubator Group Report and State of the Art Survey report has been released.
• 25/10/2007: The D2RQ Engine V0.5.1 and D2R Server V0.4 have been released. The new releases fix multiple bugs in the D2RQ Engine and allow D2R Server to be deployed within servlet containers.
• 20/01/2006: D2RQ in PHP. The University Leipzig has released a new D2RQ PHP implementation which can be used together with RAP - RDF API for PHP. See R2D2 project page for details.
• 12/05/2006: Bob DuCharme gives an interesting talk about Relational database integration with RDF/OWL using D2RQ at XML 2006.
• 10/30/2006: D2RQ V0.5 released. The new release supports SPARQL and includes a automatic mapping generator, a dump-rdf command line script, a Jena Assembler for D2RQ models. It is compatible with Jena 2.4 and ARQ 1.4 and provides improved compatibility with MySQL, Oracle and PostgreSQL. We also updated the D2RQ User Manual to reflect all new features.
• 09/08/2006: D2R Server Version 0.3 released. The new release enables database-generated URIs to be dereferenced. This allows the content of relational databases to be browsed with tool like Tabulator.
• 08/09/2006: D2RQ has been integrated into the TopBraid Composer ontology editor. Using TopBraid Composer you can browse D2RQ-mapped database content in a nice GUI, and use a professional RDF editor to customize D2RQ mapping files. See TopBraid Composer documentation for details.
• 08/02/2006: A tutorial about Triple Stores and D2RQ will be held in January 2007 at the Semantic Web School in Vienna.
• 05/09/2006: We are currently working on D2R Server. D2R Server provides SPARQL access to relational databases. The server takes SPARQL queries from the Web and rewrites them via a D2RQ mapping into SQL queries against a relational database. There will be a talk about D2R Server in the Developers Track at WWW 2006.
• 10/25/2005: D2RQ 0.4 has been published. The new version contains a wrapper which allows you to use D2RQ together with the Sesame Semantic Web framework.
• 10/15/2005: D2P Database-to-Piggybank Bridge released. D2P is an extension to the Piggybank Semantic Web browser which makes information stored in rational databases accessible to Piggybank using D2RQ mappings.
• 10/13/2005: New d2rq-map-devel mailing list. As the D2RQ user community is growing and we are receiving an increasing number of support requests and interesting new ideas around the toolkit and database to RDF mapping in general, we have opened up a D2RQ and D2R mailing list.
• 04/29/2005: D2RQ 0.3 has been published. The new version includes an experimental D2RQQueryHandler which speeds up complex RDQL queries significantly by rewriting groups of RDQL patterns into single SQL statements and by rewriting RDQL AND conditions into SQL WHERE clauses.
• 11/20/2004: D2RQ was presented at the 3rd International Semantic Web Conference (ISWC2004), Hiroshima, Japan, November 2004. See Christian Bizer, Andy Seaborne: D2RQ -Treating Non-RDF Databases as Virtual RDF Graphs. (Poster)
• 08/12/2004: D2RQ 0.2 has been published. The new version includes several language extensions and provides a significant speed-up.
• 06/29/2004: Benchmark results comparing D2RQ 0.1 and 0.2 to the Jena 2 database backend published together with the benchmarking suite.

V0.6

- Push-down and transformation of SPARQL filter expressions into SQL, if possible)
- Transformation of SPARQL optionals into SQL left joins; some cases only
- d2rq:sqlExpression
- d2rq:uriSqlExpression for properties with URI values, similar to d2rq:sqlExpression but generates URIs instead of literals (Andreas Langegger)
- New ARQ-based QueryEngine, dropped the old FastPath engine
- Support for serving vocabulary classes and properties; including definition labels, comments and additional properties
- Mapping generator now supports multi-column foreign key constraints
- Specify JDBC connection properties through the jdbc: namespace
- Better error reporting
- Oracle support - automatic registration of the JDBC driver, DATE, TIMESTAMP and CLOB field types
- Support for PostgreSQL's TIMESTAMP WITH TIME ZONE type
- Proper treatment of xsd:boolean datatype
- Show XML declaration and make sure that utf-8 encoding is used for XML
- Map parser now complains about misspelled D2RQ vocabulary terms
- Remove MySQL hack for zero date values from the mapping generator, use zeroDateTimeBehavior property instead
- Change dump-rdf default format to N-TRIPLE (faster, better streaming)
- Replaced custom Logger with Log4j one
- Give more memory to VM in dump-rdf and generate-mapping scripts
- many bugfixes

2009-02-19

V0.5.1

- columns with non-URI characters can now be used in URI patterns
- added d2rq:resultSizeLimit option
- smarter mapping generator
- many bugfixes

2007-10-24

V0.5

- supports the SPARQL query language.
- added dump-rdf command line script.
- added automatic mapping generator.
- improved compatibility with MySQL, Oracle and PostgreSQL.
- compatible with Jena 2.4 and ARQ 1.4
- added Jena Assembler for D2RQ models.
- many other improvements.
- many bugfixes.

2006-10-26

V0.4

Wrapper for Sesame added.

2005-10-25

V0.3

Language extensions:
- d2rq:queryHandler added.
- d2rq:expressionTranslator added.
- d2rq:alias added.

Speed improvements:
- New experimental D2RQQueryHandler for speeding up complex RDQL queries.

2005-04-29

V0.2

Language extensions:
- d2rq:TranslationTable between DB and RDF values added.
- d2rq:condition added; allows filtering by SQL expression.
- d2rq:AdditionalProperty added.
- d2rq:containsDuplicates hint added.
- d2rq:class added; alternative to d2rq:classMap.
- d2rq:property added; alternative to d2rq:propertyBridge.

Speed improvements:
- d2rq:valueContains performance optimization hint added.
- d2rq:valueMaxLength performance optimization hint added.
- d2rq:valueRegex performance optimization hint added.
- major speed improvement for queries with large result sets.
- major speed improvement for maps with URL columns.

Other:
- logging facility added.
- security fix: SQL injection vulnerability fixed.
- bug fix: issue with missing statements when using joins and NULL values.
- improved map consistency checking and better error messages
- GraphD2RQ and ModelD2RQ can also be initialised from RDF/XML map file.
- GraphD2RQ and ModelD2RQ can also be initialised from Jena map model.
- architectural changes for better maintainability.
- JUnit test suite added.
- many small fixes, improvements, speedups and refactorings.

2004-08-12

V0.1

Initial D2RQ Release.

2004-06-22