Guide

RDA elements

An RDA element is represented in the RDA Registry as an RDF property.

Each RDA element is assigned to one and only one RDA entity by declaring the class representing the entity as the domain of the property corresponding the element.

Every RDA property has a domain of one RDA class.

All elements that can be inherited from an entity hierarchy are explicitly identified and defined in RDA.

Example of elements reflecting class hierarchy

RDA elements are categorized as:

Map to LRM

The RDA Registry provides a Map from RDA properties to IFLA LRM.

Recording methods

Values of RDA elements may be recorded using different recording methods.

There are three methods that use a string as the value of an element:

  • An unstructured description: a plain literal, for example a free text note or a transcription.
  • A structured description: a literal typed with a form of string encoding scheme that aggregates literal values from other elements, for example an access point or structured statement.
  • An identifier: a literal that is an identifier used in a localized context, for example an ISBN or database key.

The fourth method uses an IRI as the value of an element, for example an IRI of an instance of an entity or value vocabulary.

Not all recording methods are applicable to every RDA element. There are categories of element that are intended for only one of the string methods:

  • Appellation elements for "labels" of instances of entities.
  • Note and transcription elements.

The RDA Registry provides a Map from RDA properties to recording methods.

Element set family

The RDA Registry provides datatype and object properties to support applications that use OWL semantics or otherwise want to distinguish between string and "thing" values.

Every RDA element has a datatype property with a range of Literal; every element can use a string value.

Every RDA relationship element has an object property. The range of the property is the class of the related RDA entity.

Each datatype and object property is a sub-property of the "canonical" property representing the RDA element.

RDF graph of the element set family for rdaw:P10429 has screenwriter person

RDF graph of the element set family for rdaw:P10429 "has screenwriter person". All predicates are rdfs:subPropertyOf.

All properties in a family have the same domain.

The canonical property has no declared range.

Example of domain and range declarations for rdaw:P10429 "has screenwriter person":

domain property range
rdac:C10001 "Work" rdaw:P10429
rdac:C10001 "Work" rdawd:P10429 rdfs:Literal
rdac:C10001 "Work" rdawo:P10429 rdac:C10004 "Person"

The datatype and object properties are arranged in element sets that parallel the canonical elements. This allows a regular extension to the base filepath with a standard constructor for element IRIs, as reflected in the curie prefixes used.

The range and inverse of an element are declared for the corresponding object element.