Soprano  2.7.56
Soprano (aka QRDF) - A modular RDF storage framework

Soprano is a Qt-based pluggable framework for RDF storage and parsing. It tries to provide a highly usable interface to several Resource Description Framework (RDF) storage solutions.


Soprano centers around the Soprano::Model class which represents one storage set. A Soprano::Model is basically a set of RDF quadruples, i.e. Soprano::Statement. The actual storage is done via Soprano::Backend plugins. All query operations return Soprano::Iterator instances. Iterator is an explicitly shared class which is very easy to understand and use.

Soprano makes the distinction between two types of Models: Soprano::StorageModel and Soprano::FilterModel. The former is intended to be the basic Model which actually stores the data while the latter can be stacked on top of a Soprano::StorageModel to perform certain filter operations. These filter operations can range from very basic things such as disallowing any write operation (Soprano::Util::ReadOnlyModel) to more complex things such as full text indexing of all literal statements (Soprano::Index::IndexFilterModel) or exporting the Model via D-Bus (Soprano::Server::DBusExportModel).

Apart from storage Soprano provides a system for RDF parser and serializer plugins. For more details on parsing or serializing RDF data see the Soprano::Parser and Soprano::Serializer classes.

Soprano comes with a built in Server and Client implementations allowing remote repositories to be built quickly. Soprano::Client::SparqlModel provides a client to arbitrary SPARQL (SPARQL Protocol and RDF Query Language) Http services.


(Also see the Soprano Howto for details on building Soprano applications)

Create an RDF Model:

Fill it with statements:

 model->addStatement( Soprano::Statement( QUrl( ""), Soprano::Vocabulary::RDFS::label(), Soprano::LiteralValue( "A test resource" ) ) );

Read the data back:

 Soprano::StatementIterator it = model->listStatements();
 while( ) {
    displayStatement( *it );

Query the data:

 Soprano::QueryResultIterator it = model->executeQuery( "select ?r where { ?r ?p ?o . }", Soprano::Query::QueryLanguageSparql );
 while( ) {
    displayResult( it.binding( "r" ) );


The following sections contain further information on the usage of Soprano.