Struct SortableTermEncoding 

pub struct SortableTermEncoding;

The sortable term encoding allows us to represent the expected SPARQL ordering using DataFusion’s built-in ordering for structs.

This is meant as a work-around until we can define a custom ordering in DataFusion. Alternatively, we could also write a custom operator for sorting SPARQL solutions.

Implementations

impl SortableTermEncoding

pub fn fields() -> Fields

Returns the fields of this encoding.

pub fn encode_term( &self, term: Result<TermRef<'_>, ThinError>, ) -> Result<SortableTermScalar, DataFusionError>

Encodes the term as a SortableTermScalar.

Trait Implementations

impl Debug for SortableTermEncoding

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

Formats the value using the given formatter.

impl TermEncoder<SortableTermEncoding> for TermRefSortableTermEncoder

type Term<'data> = TermRef<'data>

The value type that is being encoded.

fn encode_terms<'data>( terms: impl IntoIterator<Item = Result<<TermRefSortableTermEncoder as TermEncoder<SortableTermEncoding>>::Term<'data>, ThinError>>, ) -> Result<<SortableTermEncoding as TermEncoding>::Array, DataFusionError>

Allows encoding an iterator over RDF terms in an Arrow array.

fn encode_term( term: Result<<TermRefSortableTermEncoder as TermEncoder<SortableTermEncoding>>::Term<'_>, ThinError>, ) -> Result<<SortableTermEncoding as TermEncoding>::Scalar, DataFusionError>

Allows encoding a scalar RDF term in an Arrow scalar.

impl TermEncoder<SortableTermEncoding> for TypedValueRefSortableTermEncoder

type Term<'data> = TypedValueRef<'data>

The value type that is being encoded.

fn encode_terms<'data>( terms: impl IntoIterator<Item = Result<<TypedValueRefSortableTermEncoder as TermEncoder<SortableTermEncoding>>::Term<'data>, ThinError>>, ) -> Result<<SortableTermEncoding as TermEncoding>::Array, DataFusionError>

Allows encoding an iterator over RDF terms in an Arrow array.

fn encode_term( term: Result<<TypedValueRefSortableTermEncoder as TermEncoder<SortableTermEncoding>>::Term<'_>, ThinError>, ) -> Result<<SortableTermEncoding as TermEncoding>::Scalar, DataFusionError>

Allows encoding a scalar RDF term in an Arrow scalar.

impl TermEncoding for SortableTermEncoding

type Array = SortableTermArray

Represents a wrapper for Arrow arrays of this encoding. This can be used in conjunction with TermDecoder to obtain the values from an Arrow array.

type Scalar = SortableTermScalar

Represents a wrapper for Arrow scalars of this encoding. This can be used in conjunction with TermDecoder to obtain the values from an Arrow scalar.

fn name(&self) -> EncodingName

Returns the name of the encoding.

fn data_type(&self) -> DataType

Returns the DataType that is used for this encoding.

fn try_new_array( &self, array: Arc<dyn Array>, ) -> Result<<SortableTermEncoding as TermEncoding>::Array, DataFusionError>

Checks whether array contains a value with the correct encoding (i.e., type and possibly metadata checks). If yes, returns an instance of Self::Array. Otherwise, an error is returned.

fn try_new_scalar( &self, scalar: ScalarValue, ) -> Result<<SortableTermEncoding as TermEncoding>::Scalar, DataFusionError>

Checks whether scalar contains a value with the correct encoding (i.e., type and possibly metadata checks). If yes, returns an instance of Self::Scalar. Otherwise, an error is returned.

fn try_new_datum( &self, value: ColumnarValue, number_rows: usize, ) -> Result<EncodingDatum<Self>, DataFusionError>

Checks whether value contains a value with the correct encoding (i.e., type and possibly metadata checks). If yes, returns a datum that either wraps an array or a scalar. Otherwise, an error is returned.