Struct UnionGraph 

pub struct UnionGraph<'a, G: GraphRead + ?Sized> { /* private fields */ }

Expose the union as the default graph while preserving original named graphs. The source must remain consistent throughout a read, as a borrowed Dataset or native transaction does. A repeated exact match must select the same first quad; no sorted order is required.

Implementations

impl<'a, G: GraphRead + ?Sized> UnionGraph<'a, G>

pub fn new(source: &'a G) -> Self

Borrow a consistent source; do not clone or snapshot its base data.

Trait Implementations

impl<'source, G: GraphRead + ?Sized> GraphRead for UnionGraph<'source, G>

fn matching_quads<'a>( &'a self, subject: Option<NamedOrBlankNodeRef<'_>>, predicate: Option<NamedNodeRef<'_>>, object: Option<TermRef<'_>>, graph: Option<GraphNameRef<'_>>, ) -> impl Iterator<Item = Result<Quad>> + use<'a, 'source, G>

Stream matching quads. Read failures must remain errors, never omissions. Retain the source borrow, not the caller’s temporary pattern references.

fn named_graphs(&self) -> impl Iterator<Item = Result<NamedOrBlankNode>> + '_

Stream each named graph exactly once, including empty backend graphs. Iteration must not materialize the set of graph names.

fn contains_named_graph(&self, graph: &NamedOrBlankNode) -> Result<bool>

Test graph existence, including empty graphs in capable storage backends.