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QueryRDF

rudof_rdf::rdf_core::query

Trait QueryRDF 

Source 
pub trait QueryRDF: Rdf {
    // Required methods
    fn query_select(
        &self,
        query: &str,
    ) -> Result<QuerySolutions<Self>, Self::Err>
       where Self: Sized;
    fn query_construct(
        &self,
        query: &str,
        result_format: &QueryResultFormat,
    ) -> Result<String, Self::Err>
       where Self: Sized;
    fn query_ask(&self, query: &str) -> Result<bool, Self::Err>;
}
Expand description

Trait for RDF graphs that support SPARQL query execution.

This trait extends Rdf with methods for executing SPARQL queries against the RDF graph. SPARQL is the W3C standard query language for RDF, providing pattern matching, filtering, and graph construction capabilities.

§Query Forms

SPARQL defines four query forms, three of which are supported by this trait:

  • SELECT: Pattern matching that returns variable bindings as a table
  • CONSTRUCT: Pattern matching that builds a new RDF graph from templates
  • ASK: Boolean query testing whether a pattern exists in the graph
  • DESCRIBE (not yet supported): Retrieves RDF data about resources

Required Methods§

Source

fn query_select(&self, query: &str) -> Result<QuerySolutions<Self>, Self::Err>
where Self: Sized,

Executes a SPARQL SELECT query and returns variable bindings.

SELECT queries match patterns in the RDF graph and return a table-like structure containing variable bindings for each match. This is the most common SPARQL query form, analogous to SELECT in SQL.

§Arguments
  • query - A SPARQL SELECT query string
Source

fn query_construct( &self, query: &str, result_format: &QueryResultFormat, ) -> Result<String, Self::Err>
where Self: Sized,

Executes a SPARQL CONSTRUCT query and returns a serialized RDF graph.

CONSTRUCT queries match patterns in the RDF graph and use those matches to build a new RDF graph according to a template. The resulting graph is serialized to a string in the specified format.

§Arguments
  • query - A SPARQL CONSTRUCT query string
  • result_format - The serialization format for the resulting RDF graph (e.g., Turtle, RDF/XML, N-Triples)
Source

fn query_ask(&self, query: &str) -> Result<bool, Self::Err>

Executes a SPARQL ASK query and returns a boolean result.

ASK queries test whether a pattern exists in the RDF graph. They return true if at least one solution to the query pattern exists, false otherwise. This is more efficient than SELECT when only existence needs to be checked.

§Arguments
  • query - A SPARQL ASK query string

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§