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pl:miw:miw2009_llvm [2010/01/11 19:59] jsi09 |
pl:miw:miw2009_llvm [2019/06/27 15:50] (aktualna) |
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| + | http://www.ldodds.com/projects/twinkle/twinkle-2.0-src.zip | ||
| + | \\ | ||
| + | \\ | ||
| **Redland RDF Libraries**\\ | **Redland RDF Libraries**\\ | ||
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| License \\ | License \\ | ||
| All Redland packages are free software / open source software and released under the LGPL 2.1, GPL 2 or Apache 2 licenses as alternatives. See the individual package license files for full details and any exceptions.\\ | All Redland packages are free software / open source software and released under the LGPL 2.1, GPL 2 or Apache 2 licenses as alternatives. See the individual package license files for full details and any exceptions.\\ | ||
| + | \\ | ||
| + | http://download.librdf.org/ | ||
| + | \\ | ||
| + | \\ | ||
| **ARQ** \\ \\ | **ARQ** \\ \\ | ||
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| Jena storage engines that plug into ARQ include: | Jena storage engines that plug into ARQ include: | ||
| * TDB -- Custom storage engine for high performance applications | * TDB -- Custom storage engine for high performance applications | ||
| - | * SDB -- Rewriter to SQL for transactional SPARQL on standard relational databases | + | * SDB -- Rewriter to SQL for transactional SPARQL on standard relational databases\\ |
| + | \\ | ||
| + | http://sourceforge.net/projects/jena/files/ARQ/ | ||
| + | \\ | ||
| + | \\ | ||
| ====== SWI-Prolog semantic Web serwer with sparql/serql ====== | ====== SWI-Prolog semantic Web serwer with sparql/serql ====== | ||
| + | **Introduction** | ||
| + | \\ | ||
| + | The SWI-Prolog Semantic Web Server unifies the SWI-Prolog general Web support and Semantic Web support, providing both a starting point for dedicated applications and a platform for exchange of RDF-based data using a standardised language and protocol. An overview of the SWI-Prolog Web support libraries can be found in SWI-Prolog and the Web,1Submitted to Theory and Practice of Logic Programming\\ \\ | ||
| + | Query Languages | ||
| + | \\ \\ | ||
| + | The current server supports two query languages: SeRQL and SPARQL. For both languages we provide an interactive service that presents the results as a human-readable HTML table, a service presenting its result as RDF/XML or XML that follows the HTTP protocol definition for the query language, the possibility to query the local database using a query language in Prolog and a Prolog client that can be used to query remote services supporting the query language and HTTP service. | ||
| + | \\ \\ | ||
| + | For both query languages, queries are translated to a complex Prolog goal calling rdf/3 to resolve edges in the graph and calls to predicates from rdfql_runtime.pl that realise constraints imposed by the SeRQL WHERE clause and SPARQL FILTER clauses. | ||
| + | \\ \\ | ||
| + | SPARQL Support | ||
| + | \\ \\ | ||
| + | SPARQL support is based on the SPARQL specification, versioned April 6, 2006. Status: | ||
| + | \\ | ||
| + | * No query optimization | ||
| + | * Limited value-testing, notably on xsd:dateTime | ||
| + | * Incomplete ORDER BY support. Only ascending and all values are compared lexically. | ||
| + | * No support for named graphs | ||
| + | * Passes current test-suite, except tests affected by the above or acknowledged as errornous. | ||
| + | |||
| + | \\ | ||
| + | SeRQL Support | ||
| + | \\ | ||
| + | SeRQL support and compatibility is based on development version 20040820, with additional support for the new 1.2 syntax and some of the built-in functions. Both SeRQL and the HTTP API are fully defined in the Sesame documentation. | ||
| **Installation and Administration** | **Installation and Administration** | ||
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| sparql_query(+Query, -Answer, +Options) | sparql_query(+Query, -Answer, +Options) | ||
| Similar to serql_query/3. | Similar to serql_query/3. | ||
| + | \\ \\ | ||
| + | **Query optimisation** | ||
| + | \\ \\ | ||
| + | By default, but under control of the setting/1 option optimise_query(Bool), and the option optimise(Bool), the query compiler optimises initial goal obtained from naive translation of the query text. The optimiser is defined in rdf_optimise.pl. The optimiser is described in detail in An optimised Semantic Web query language implementation in Prolog. The optimiser reorders goals in the generated conjunction and prepares for independent execution of independent parts of the generated goal. With the optimiser enabled (default), the provided order of path-expressions on the query text is completely ignored and constraints are inserted at the earliest possible point. | ||
| + | \\ \\ | ||
| + | The SeRQL LIKE operator applies to both resources and literals, while the SWI-Prolog RDF-DB module can only handle LIKE efficiently on literals. The optimiser can be made aware of this using WHERE label(X) LIKE "joe*". Taking the label informs the optimiser that it only needs to consider literals. Likewise, equivalence tests where one of the arguments is used as subject or predicate or has the isResource(X) constraint tell the system it can do straight identifier comparison rather then the much more expensive general comparison. | ||
| + | \\ \\ | ||
| + | Query optimisation is not yet supported for SPARQL. | ||
| + | \\ \\ | ||
| + | **Webserver** | ||
| + | \\ \\ | ||
| + | The webserver is realised by server.pl, merely loading both components: http_data.pl providing the Sesame HTTP API using the same paths and parameters and http_user.pl providing a browser-friendly frontend. Error messages are still very crude and almost all errors return a 500 server error page with a transcription of the Prolog exception. | ||
| + | \\ \\ | ||
| + | The Sesame HTTP API deals with a large number of data formats, only part of which are realised by the current system. This realisation is achieved through rdf_result, providing an extensible API for reading and writing in different formats. rdf_html, rdf_write and xml_result provide some implementations thereof. | ||
| + | \\ \\ | ||
| + | |||
| + | |||
| + | |||
| **The Sesame client**\\ | **The Sesame client**\\ | ||
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| ====== Interesting documentation about SWI-Prolog and SPARQL====== | ====== Interesting documentation about SWI-Prolog and SPARQL====== | ||
| - | * {{:pl:miw:2009:SEM_WEB_PROLOG.pdf|}} | + | * {{:pl:miw:SEM_WEB_PROLOG.pdf|}} |
| - | * {{:pl:miw:2009:SeRQLinProlog.pdf|}} | + | * {{:pl:miw:SeRQLinProlog.pdf|}} |
| ====== Important links ====== | ====== Important links ====== | ||
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| http://dbtune.org/jamendo/store/documentation.html#sec:7 \\ | http://dbtune.org/jamendo/store/documentation.html#sec:7 \\ | ||
| http://webhosting.pl/Sieci.Semantyczne:.W3C.publikuje.standard.jezyka.SPARQL \\ | http://webhosting.pl/Sieci.Semantyczne:.W3C.publikuje.standard.jezyka.SPARQL \\ | ||
| - | http://pl.wikipedia.org/wiki/J%C4%99zyk_zapyta%C5%84 \\ | + | |
| - | http://pl.wikinews.org/wiki/SPARQL_-_j%C4%99zyk_zapyta%C5%84_dla_semantycznej_sieci_od_W3C \\ | + | |
| - | http://www.heise-online.pl/newsticker/news/item/Organizacja-W3C-opublikowala-standard-SPARQL-772360.html \\ | + | |
