Data Graphs RDF graph sources for triples. Data graphs are used in the query to describe RDF graphs that can be used to query against. The graphs can be used either with #raptor_uri to name the graph, or without a name. The query language determines which graphs are used in the query. @uri: @name_uri: @flags: @uri: @name_uri: @flags: @Returns: @dg: @RASQAL_DATA_GRAPH_NONE: @RASQAL_DATA_GRAPH_NAMED: @RASQAL_DATA_GRAPH_BACKGROUND: @dg: @fh: