Struct PreparedQuery 

pub struct PreparedQuery<'a> { /* private fields */ }

A prepared SPARQL query.

Allows customizing things like the evaluation dataset and substituting variables.

Usage example:

use oxrdf::{Dataset, Literal, Variable};
use spareval::{QueryEvaluator, QueryResults};
use spargebra::SparqlParser;

let query = SparqlParser::new().parse_query("SELECT ?v WHERE {}")?;
let evaluator = QueryEvaluator::new();
let prepared_query = evaluator
    .prepare(&query)
    .substitute_variable(Variable::new("v")?, Literal::from(1));

if let QueryResults::Solutions(mut solutions) = prepared_query.execute(&Dataset::new())? {
    assert_eq!(
        solutions.next().unwrap()?.get("v"),
        Some(&Literal::from(1).into())
    );
}

Implementations

impl PreparedQuery<'_>

pub fn substitute_variable( self, variable: impl Into<Variable>, term: impl Into<Term>, ) -> Self

Substitute a variable with a given RDF term in the SPARQL query.

Usage example:

use oxrdf::{Dataset, Literal, Variable};
use spareval::{QueryEvaluator, QueryResults};
use spargebra::SparqlParser;

let query = SparqlParser::new().parse_query("SELECT ?v WHERE {}")?;
let evaluator = QueryEvaluator::new();
let prepared_query = evaluator
    .prepare(&query)
    .substitute_variable(Variable::new("v")?, Literal::from(1));

if let QueryResults::Solutions(mut solutions) = prepared_query.execute(&Dataset::new())? {
    assert_eq!(
        solutions.next().unwrap()?.get("v"),
        Some(&Literal::from(1).into())
    );
}

pub fn dataset(&self) -> &QueryDatasetSpecification

Returns the query dataset specification of this prepared query.

pub fn dataset_mut(&mut self) -> &mut QueryDatasetSpecification

Returns the query dataset specification of this prepared query.

pub fn execute<'b>( self, dataset: impl QueryableDataset<'b>, ) -> Result<QueryResults<'b>, QueryEvaluationError>

Execute the SPARQL query against the given QueryableDataset.

pub fn explain<'b>( self, dataset: impl QueryableDataset<'b>, ) -> (Result<QueryResults<'b>, QueryEvaluationError>, QueryExplanation)

Trait Implementations

impl<'a> Clone for PreparedQuery<'a>

fn clone(&self) -> PreparedQuery<'a>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.