Amazon Neptune
User Guide (API Version 2017-11-29)

SPARQL Default Graph and Named Graphs

Amazon Neptune associates every triple with a named graph. The default graph is defined as the union of all named graphs.

Default Graph for Queries

If you submit a SPARQL query without explicitly specifying a graph via the GRAPH keyword or constructs such as FROM NAMED, Neptune always considers all triples in your DB instance. For example, the following query returns all triples from a Neptune SPARQL endpoint: SELECT * WHERE { ?s ?p ?o }. Triples that appear in more than one graph are returned only once.

For information about the default graph specification, see the RDF Dataset section of the SPARQL 1.1 Query Language specification.

Specifying the Named Graph for Loading, Inserts, or Updates

If you don't specify a named graph when loading, inserting, or updating triples, Neptune uses the fallback named graph defined by the URI http://aws.amazon.com/neptune/vocab/v01/DefaultNamedGraph.

When you issue a Neptune Load request using a triple-based format, you can specify the named graph to use for all triples by using the parserConfiguration: namedGraphUri parameter. For information about the Load command syntax, see Neptune Loader Command.

Important

If you don't use this parameter, and you don't specify a named graph, the fallback URI is used: http://aws.amazon.com/neptune/vocab/v01/DefaultNamedGraph.

This fallback named graph is also used if you load triples via SPARQL UPDATE without explicitly providing a named graph target.

You can use the quads-based format N-Quads to specify a named graph for each triple in the database.

Note

Using N-Quads allows you to leave the named graph blank. In this case, http://aws.amazon.com/neptune/vocab/v01/DefaultNamedGraph is used.

You can override the default named graph for N-Quads using the namedGraphUri parser configuration option.