Struct oxrdf::dataset::Dataset

pub struct Dataset { /* private fields */ }

An in-memory RDF dataset.

It can accommodate a fairly large number of quads (in the few millions). Beware: it interns the string and does not do any garbage collection yet: if you insert and remove a lot of different terms, memory will grow without any reduction.

Usage example:

use oxrdf::*;

let mut dataset = Dataset::default();

// insertion
let ex = NamedNodeRef::new("http://example.com")?;
let quad = QuadRef::new(ex, ex, ex, ex);
dataset.insert(quad);

// simple filter
let results: Vec<_> = dataset.quads_for_subject(ex).collect();
assert_eq!(vec![quad], results);

// direct access to a dataset graph
let results: Vec<_> = dataset.graph(ex).iter().collect();
assert_eq!(vec![TripleRef::new(ex, ex, ex)], results);

Implementations

impl Dataset

pub fn new() -> Self

Creates a new dataset

pub fn graph<'a, 'b>( &'a self, graph_name: impl Into<GraphNameRef<'b>> ) -> GraphView<'a>

Provides a read-only view on an RDF graph contained in this dataset.

use oxrdf::*;

let mut dataset = Dataset::default();
let ex = NamedNodeRef::new("http://example.com")?;
dataset.insert(QuadRef::new(ex, ex, ex, ex));

let results: Vec<_> = dataset.graph(ex).iter().collect();
assert_eq!(vec![TripleRef::new(ex, ex, ex)], results);

pub fn graph_mut<'a, 'b>( &'a mut self, graph_name: impl Into<GraphNameRef<'b>> ) -> GraphViewMut<'a>

Provides a read/write view on an RDF graph contained in this dataset.

use oxrdf::*;

let mut dataset = Dataset::default();
let ex = NamedNodeRef::new("http://example.com")?;

// We edit and query the dataset http://example.com graph
{
    let mut graph = dataset.graph_mut(ex);
    graph.insert(TripleRef::new(ex, ex, ex));
    let results: Vec<_> = graph.iter().collect();
    assert_eq!(vec![TripleRef::new(ex, ex, ex)], results);
}

// We have also changes the dataset itself
let results: Vec<_> = dataset.iter().collect();
assert_eq!(vec![QuadRef::new(ex, ex, ex, ex)], results);

pub fn iter(&self) -> Iter<'_>

Returns all the quads contained by the dataset.

pub fn quads_for_subject<'a, 'b>( &'a self, subject: impl Into<SubjectRef<'b>> ) -> impl Iterator<Item = QuadRef<'a>> + 'a

pub fn quads_for_predicate<'a, 'b>( &'a self, predicate: impl Into<NamedNodeRef<'b>> ) -> impl Iterator<Item = QuadRef<'a>> + 'a

pub fn quads_for_object<'a, 'b>( &'a self, object: impl Into<TermRef<'b>> ) -> impl Iterator<Item = QuadRef<'a>> + 'a

pub fn contains<'a>(&self, quad: impl Into<QuadRef<'a>>) -> bool

Checks if the dataset contains the given quad

pub fn len(&self) -> usize

Returns the number of quads in this dataset.

pub fn is_empty(&self) -> bool

Checks if this dataset contains a quad.

pub fn insert<'a>(&mut self, quad: impl Into<QuadRef<'a>>) -> bool

Adds a quad to the dataset.

pub fn remove<'a>(&mut self, quad: impl Into<QuadRef<'a>>) -> bool

Removes a concrete quad from the dataset.

pub fn clear(&mut self)

Clears the dataset.

pub fn canonicalize(&mut self)

Applies on the dataset the canonicalization process described in Canonical Forms for Isomorphic and Equivalent RDF Graphs: Algorithms for Leaning and Labelling Blank Nodes, Aidan Hogan, 2017.

Usage example (Dataset isomorphism):

use oxrdf::*;

let iri = NamedNodeRef::new("http://example.com")?;

let mut graph1 = Graph::new();
let bnode1 = BlankNode::default();
let g1 = BlankNode::default();
graph1.insert(QuadRef::new(iri, iri, &bnode1, &g1));
graph1.insert(QuadRef::new(&bnode1, iri, iri, &g1));

let mut graph2 = Graph::new();
let bnode2 = BlankNode::default();
let g2 = BlankNode::default();
graph2.insert(QuadRef::new(iri, iri, &bnode2, &g2));
graph2.insert(QuadRef::new(&bnode2, iri, iri, &g2));

assert_ne!(graph1, graph2);
graph1.canonicalize();
graph2.canonicalize();
assert_eq!(graph1, graph2);

Warning 1: Blank node ids depends on the current shape of the graph. Adding a new quad might change the ids of a lot of blank nodes. Hence, this canonization might not be suitable for diffs.

Warning 2: The canonicalization algorithm is not stable and canonical blank node ids might change between Oxigraph version.

Warning 3: This implementation worst-case complexity is in O(b!) with b the number of blank nodes in the input dataset.

Trait Implementations

impl Debug for Dataset

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Dataset

fn default() -> Dataset

Returns the “default value” for a type.

impl Display for Dataset

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Extend<Quad> for Dataset

fn extend<I: IntoIterator<Item = Quad>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<'a, T: Into<QuadRef<'a>>> Extend<T> for Dataset

fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl FromIterator<Quad> for Dataset

fn from_iter<I: IntoIterator<Item = Quad>>(iter: I) -> Self

Creates a value from an iterator.

impl<'a, T: Into<QuadRef<'a>>> FromIterator<T> for Dataset

fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self

Creates a value from an iterator.

impl<'a> IntoIterator for &'a Dataset

type Item = QuadRef<'a>

The type of the elements being iterated over.

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Iter<'a>

Creates an iterator from a value.

impl PartialEq<Dataset> for Dataset

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Dataset