Package rdflib.sparql

TODO: merge this first bit from sparql.sparql.py into rest of doc... updating all along the way.

SPARQL implementation on top of RDFLib

Implementation of the <a href="http://www.w3.org/TR/rdf-sparql-query/">W3C SPARQL</a> language (version April 2005). The basic class here is supposed to be a superclass of rdflib.sparql.sparqlGraph; it has been separated only for a better maintainability.

There is a separate description for the functionalities.

For a general description of the SPARQL API, see the separate, more complete description.

Variables, Imports

The top level (__init__.py) module of the Package imports the important classes. In other words, the user may choose to use the following imports only:

   from rdflibUtils   import myTripleStore
   from rdflibUtils   import retrieveRDFFiles
   from rdflibUtils   import SPARQLError
   from rdflibUtils   import GraphPattern

The module imports and/or creates some frequently used Namespaces, and these can then be imported by the user like:

   from rdflibUtils import ns_rdf

Finally, the package also has a set of convenience string defines for XML Schema datatypes (ie, the URI-s of the datatypes); ie, one can use:

   from rdflibUtils import type_string
   from rdflibUtils import type_integer
   from rdflibUtils import type_long
   from rdflibUtils import type_double
   from rdflibUtils import type_float
   from rdflibUtils import type_decimal
   from rdflibUtils import type_dateTime
   from rdflibUtils import type_date
   from rdflibUtils import type_time
   from rdflibUtils import type_duration

These are used, for example, in the sparql-p implementation.

The three most important classes in RDFLib for the average user are Namespace, URIRef and Literal; these are also imported, so the user can also use, eg:

   from rdflibUtils import Namespace, URIRef, Literal

History

Version 1.0: based on an earlier version of the SPARQL, first released implementation
Version 2.0: version based on the March 2005 SPARQL document, also a major change of the core code (introduction of the separate GraphPattern class, etc).
Version 2.01: minor changes only: - switch to epydoc as a documentation tool, it gives a much better overview of the classes - addition of the SELECT * feature to sparql-p
Version 2.02: - added some methods to myTripleStore to handle Alt and Bag the same way as Seq - added also methods to add collections and containers to the triple store, not only retrieve them
Version 2.1: adapted to the inclusion of the code into rdflib, thanks to Michel Pelletier
Version 2.2: added the sorting possibilities; introduced the Unbound class and have a better interface to patterns using this (in the BasicGraphPattern class)

Version: 2.2

Author: Ivan Herman

Contact: Ivan Herman, ivan@ivan-herman.net

License: This software is available for use under the W3C Software License

Submodules

Submodules
`graphPattern`: Graph pattern class used by the SPARQL implementation `parser`: SPARQL Lexer, Parser and Function-Mapper By Shawn Brown <http://shawnbrown.com/contact> TO DO: swap current parser functions for Michelp's pyparsing setup add mapping for FILTER/constraints typed literals integer, double or boolean abbreviations language tags (e.g., @fr) nested OPTIONALs ??? blank node and RDF collection syntax ??? GRAPH statements ??? CURRENTLY SUPPORTED: Simple SELECT queries Predicate-object and object list shorthand (e.g., ?x foaf:name ?name ; foaf:mbox ?mbox ; vcard:TITLE ?title) Multi-line/triple-quoted literals BASE, PREFIX, SELECT, WHERE, UNION, OPTIONAL, multiple UNIONs and multiple OPTIONALs (but not nested OPTIONALs) USAGE: #from sparql_lpm import doSPARQL from rdflib.sparql.parser import doSPARQL ...load graph... `Query` `QueryResult` `sparqlGraph` `sparqlOperators` `Unbound`

graphPattern: Graph pattern class used by the SPARQL implementation
parser: SPARQL Lexer, Parser and Function-Mapper By Shawn Brown <http://shawnbrown.com/contact> TO DO: swap current parser functions for Michelp's pyparsing setup add mapping for FILTER/constraints typed literals integer, double or boolean abbreviations language tags (e.g., @fr) nested OPTIONALs ??? blank node and RDF collection syntax ??? GRAPH statements ??? CURRENTLY SUPPORTED: Simple SELECT queries Predicate-object and object list shorthand (e.g., ?x foaf:name ?name ; foaf:mbox ?mbox ; vcard:TITLE ?title) Multi-line/triple-quoted literals BASE, PREFIX, SELECT, WHERE, UNION, OPTIONAL, multiple UNIONs and multiple OPTIONALs (but not nested OPTIONALs) USAGE: #from sparql_lpm import doSPARQL from rdflib.sparql.parser import doSPARQL ...load graph...
Query
QueryResult
sparqlGraph
sparqlOperators
Unbound

Classes
`Processor`

Exceptions
`SPARQLError`	Am SPARQL error has been detected

Function Summary
a function suitable as a sparql filter	`generateCollectionConstraint(triplets, collection, item)` Generate a function that can then be used as a global constaint in sparql to check whether the 'item' is an element of the 'collection' (a.k.a.

Function Details

generateCollectionConstraint(triplets, collection, item)

Generate a function that can then be used as a global constaint in sparql to check whether the 'item' is an element of the 'collection' (a.k.a. list). Both collection and item can be a real resource or a query string. Furthermore, item might be a plain string, that is then turned into a literal run-time.

The function returns an adapted filter method that can then be plugged into a sparql request.

Parameters:: triplets - the SPARQLGraph instance; collection - is either a query string (that has to be bound by the query) or an RDFLib Resource representing the collection; item - is either a query string (that has to be bound by the query) or an RDFLib Resource that must be tested to be part of the collection

Returns:: a function suitable as a sparql filter

Raises:: SPARQLError - if the collection or the item parameters are illegal (not valid resources for a collection or an object)

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