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Questions tagged [redland]

Redland is a set of free C libraries providing support for Resource Description Framework (RDF) data.

Redland is a set of free C libraries providing support for Resource Description Framework (RDF) data.

Redland consists of the following parts:

  • Raptor RDF Syntax Library for parsing and serializing RDF syntaxes

  • Rasqal RDF Query Library for executing RDF queries

  • Redland RDF Library (librdf) providing the RDF API and triple stores, building on top of Raptor and Rasqal

  • Redland Language Bindings for language APIs to Redland in Perl, PHP, Python and Ruby

Use this tag for questions about using any of the above libraries.

Related tags:

Redland website

41 questions
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What's the character encoding for string representations of URIs in Redland RDF?

Is it safe to assume that strings returned by librdf_uri_as_string () use UTF-8 encoding. Or is it perhaps ISO-Latin (with additional URL encoding)? I am dealing with URIs in an librdf_model that was read with…
Drux
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Redland RDF libraries: why does parsing model from Turtle without base URI cause error?

Why does the following test produce an error? Does Redland's turtle parser insist on a base URI even if all actual URIs are absolute? (Apache Jena apparently does not.) And how could I find out more about what actually went wrong (i.e. what API call…
Drux
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Lifetime of RDF nodes in Redland RDF after parsing a model?

I am parsing an RDF_model using librdf_parser_parse_string_into_model. I then retain the librdf_model but free the librdf_parser. It looks to me as if the nodes in the model then have disappeared as well. So what lifetime does Redland RDF impose on…
Drux
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building raptor RDF from Source on OSX

I am trying to build the Raptor RDF Syntax Library. I can successfully install it using homebrew but would like to build from source instead. However, LIBTOOLIZE=/usr/bin/glibtoolize ./autogen.sh autogen.sh: Looking for programs: automake aclocal…
ejang
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Problem with queries, Redland and python bindings

I'm developing a semantic reverse proxy that extracts metadata. I use Django, dj-revproxy and RDFLib (and for the storage I use MySQL), but i'm switching to redland's framework with the python bindings for the management of the semantic part. But I…
sLoK
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Comparing two RDF/XML files using Raptor and also generating differences?

I want to write Python script using Raptor to compare two RDF files where the 2nd RDF file would have a a specific format that the 1st one should follow. If there is a difference, then I want to print that difference. No luck with W3...
Apoorv Kudesia
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RDF-raptor-parser

I am trying to parse the rdf file but I am getting error while executing following code in ubuntu RDF::Reader.open("http://datagraph.org/jhacker/foaf.rdf") do |reader| reader.each_statement do |statement| puts statement.inspect end end as…
naveen
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Redland Python bindings very slow inserts

I am tetsing out Redland's Python bindings. From some simple tests, inserting data seems many, many times slower than RDFLib. A simple script such as: import RDF h1=RDF.HashStorage( "/var/tmp/redland.bdb", options="hash-type='bdb',…
user3758232
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Remove triples with no context from a Redland graph

I am using the Redland librdf library and would like to remove all triples with no associated context node from a graph. I tried passing NULL as the context node pointer to librdf_model_context_remove_statements, but that results in…
Nicholas Shanks
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How to define type of object in Redland R RDF triples

I'm trying to use the Redland R RDF implementation to construct a simple RDF store but am having problems writing non-literal triples. In code, after setting up world and model, whilst the literal triple addStatement(model, …
drw
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Using Sqlite3 as Redland RDF storage on iOS with Redland-ObjC

I'm trying to use https://github.com/p2/Redland-ObjC, that compiles and runs fine on iOS to store RDF triples in the iOS sqlite3 database. However, documentation is very light, and Redland-ObjC seems to only use Redland storage with an in-memory…
webaba
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Fast insertion of rdf triples using redland/c++

I went over the redland documentation and there are some problems I couldn't be certain of solving. Looking on a c++ side, suppose you generate numerous rdf triples over time for several different graphs, and knowing it is not interested a primary…
leag
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redland rapper/libraptor2 running out of memory on large RDF file

I'm trying to parse the Turtle dump from the Freebase Data Dumps using libraptor2 [version 2-2.0.10], and my program runs out of memory. So, I tried using the "rapper" program and the results are same (runs out of memory): # …
Shanti Adhikari
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Multiple Redland RDF models seem to contain the same RDF nodes from the model that was parsed last

I've now isolated a problem with the Redland RDF libraries that I had also previously asked about. So I'm still wondering: what causes the following test case to fail? Essentially what should happen is the following: I'm constructing two RDF models,…
Drux
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RDF::Reader > Problems with URI::InvalidError

I have problems with this code: require 'rubygems' require 'rdf' require 'rdf/raptor' RDF::Reader.open("http://reegle.info/countries/IN.rdf") do |reader| reader.each_statement do |statement| puts statement.inspect end end When trying to…
auralbee
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