Crate oxigraph 

Oxigraph

Oxigraph is a graph database library implementing the SPARQL standard.

Its goal is to provide a compliant, safe and fast on-disk graph database. It also provides a set of utility functions for reading, writing, and processing RDF files.

Oxigraph is in heavy development and SPARQL query evaluation has not been optimized yet.

Oxigraph also provides a CLI tool and a Python library based on this library.

Oxigraph implements the following specifications:

• SPARQL 1.1 Query, SPARQL 1.1 Update, and SPARQL 1.1 Federated Query.
• Turtle, TriG, N-Triples, N-Quads, and RDF/XML RDF serialization formats for both data ingestion and retrieval.
• SPARQL Query Results XML Format, SPARQL 1.1 Query Results JSON Format and SPARQL 1.1 Query Results CSV and TSV Formats.

Support for RDF 1.2 and SPARQL 1.2 is also available behind the rdf-12 feature.

A preliminary benchmark is provided. Oxigraph internal design is described on the wiki.

The main entry point of Oxigraph is the Store struct:

use oxigraph::model::*;
use oxigraph::sparql::{QueryResults, SparqlEvaluator};
use oxigraph::store::Store;

let store = Store::new().unwrap();

// insertion
let ex = NamedNode::new("http://example.com").unwrap();
let quad = Quad::new(ex.clone(), ex.clone(), ex.clone(), GraphName::DefaultGraph);
store.insert(&quad).unwrap();

// quad filter
let results = store
    .quads_for_pattern(Some(ex.as_ref().into()), None, None, None)
    .collect::<Result<Vec<Quad>, _>>()
    .unwrap();
assert_eq!(vec![quad], results);

// SPARQL query
if let QueryResults::Solutions(mut solutions) = SparqlEvaluator::new()
    .parse_query("SELECT ?s WHERE { ?s ?p ?o }")
    .unwrap()
    .on_store(&store)
    .execute()
    .unwrap()
{
    assert_eq!(
        solutions.next().unwrap().unwrap().get("s"),
        Some(&ex.into())
    );
}

It is based on these crates that can be used separately:

• oxrdf, datastructures encoding RDF basic concepts (the oxigraph::model module).
• oxrdfio, a unified parser and serializer API for RDF formats (the oxigraph::io module). It itself relies on:
  • oxttl, N-Triple, N-Quad, Turtle, TriG and N3 parsing and serialization.
  • oxrdfxml, RDF/XML parsing and serialization.
• spargebra, a SPARQL parser.
• sparesults, parsers and serializers for SPARQL result formats (the oxigraph::sparql::results module).
• sparopt, a SPARQL optimizer.
• oxsdatatypes, an implementation of some XML Schema datatypes.

To build the library locally, don’t forget to clone the submodules using git clone --recursive https://github.com/oxigraph/oxigraph.git to clone the repository including submodules or git submodule update --init to add submodules to the already cloned repository.

It is possible to disable the RocksDB storage backend to only use the in-memory fallback by disabling the rocksdb default feature:

oxigraph = { version = "*", default-features = false }

This is the default behavior when compiling Oxigraph to WASM.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or <http://www.apache.org/licenses/LICENSE-2.0>)
• MIT license (LICENSE-MIT or <http://opensource.org/licenses/MIT>)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Oxigraph by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Modules

io

Utilities to read and write RDF graphs and datasets using OxRDF I/O.

model

Implements data structures for RDF 1.1 Concepts using OxRDF.

sparql

SPARQL implementation.

store

API to access an on-disk RDF dataset.