Crate rdf_fusion_encoding 

Contains the RDF Funion’s term encodings.

Overview

RDF term encodings allow us to bridge the gap between the Resource Description Framework and the Arrow type system. Because there is no single best way to represent RDF terms in Arrow, RDF Fusion supports multiple encodings. The documentation of the main crate provides some further details on this aspect.

The following table provides an overview of the supported encodings.

	Suitable For	Requirements	Term Identity	Comment
String Encoding	Simplicity	-	Yes
Plain Term	Processing literal terms	-	Yes	Result visible to users
Object ID	Joining solution sets	Object ID Mapping	Yes	Must be decoded at some point
Typed Family	Arithmetic and comparisons	-	No

Encoding Trait

All of the above encodings must implement the TermEncoding trait. As a result, each encoding must provide an EncodingArray and an EncodingScalar. These two types wrap regular Arrow arrays (or scalars) that adhere to a particular encoding. If you want to pass an array to a function that is guaranteed to be of a certain encoding, use these data types.

Modules

compute

Contains computations that mostly map between different encodings.

object_id

plain_term

string

typed_family

Structs

QuadStorageEncodingNameParserError

RdfFusionEncodings

Holds a configuration instance for each RDF Fusion encoding.

Enums

DowncastEncodingArgs

Represents a list of arrays that share the same encoding.

EncodingDatum

Represents either an array or a scalar for a given encoding.

EncodingName

Represents the name of a single TermEncoding.

QuadStorageEncoding

Defines which encoding is used for retrieving quads from the storage.

QuadStorageEncodingName

A version of QuadStorageEncoding that only reflects the name of the encoding.

Traits

EncodingArray

Represents an Arrow Array with a specific TermEncoding.

EncodingScalar

Represents an Arrow ScalarValue with a specific TermEncoding.

ScalarEncoder

Is responsible for encoding RDF terms (or NULL) in a particular encoding.

TermDecoder

Allows extracting an iterator of a type from an EncodingArray.

TermEncoder

Allows encoding an iterator of a type into an EncodingArray.

TermEncoding

A term encoding defines how RDF terms are represented in Arrow arrays.

Functions

detect_encoding_from_types

Detects the encoding of the given argument types.

quads_to_plain_term_dataframe

Creates a DataFrame from the given quads using the plain term encoding.

quads_to_plain_term_record_batch

Creates a RecordBatch from the given quads using the plain term encoding.