1. RDA Community and linked data
Gordon Dunsire
LD4 Workshop, 1 May 2018

2. Kinds of recorded data
RDA is designed to support a wide range of data carrier architectures for storage and display
Flat-file: card and other print-based catalogues
Local
(Closed-world)
Bib/Authority: MARC, etc.
RDBMS: Table for each entity, row keys (IDs)
Global (Open-world)
RDF: Classes, properties, and IRIs
RDA uses RDF to record data for RDA Reference (entities, elements, and vocabulary encoding schemes)
RDA/RDF provides data for
RDA Toolkit (Glossary, element reference, navigation)
Available from RDA Registry under open license

3. RDA recording methods
RDA provides instructions for four methods of recording data values:
Unstructured description
Transcription; free-form notes; uncontrolled human-readable appellation (name, title)
Structured description
Multiple values with string encoding scheme; value with syntax encoding scheme; controlled human-readable appellation (access point)
Identifier
Machine-readable appellation (local)
IRI
Machine-readable appellation (global)
An appellation references an instance of an entity

4. Recording methods for related data
"note on related entity 2"
Keyword index
"access point for related entity 2"
Authority file
RDA Entity 1
is related to
Standard identifier system
"identifier for related entity 2"
This diagram shows all four recording methods in use to reference a related entity.
The diagram can be interpreted as an RDF graph for linked data, or as a relational schema for a local database.
RDA Entity 2
Semantic Web

5. Strings, things, and Nomens
Entity
(thing)
has appellation
has nomen string
Nomen
“nomen string"
Status
(VES)
Timespan
has date of usage
has status of
identification
Name
Authority
file

6. Beyond RDA
RDA is an implementation of the IFLA Library Reference Model
RDA
Entity
LRM
Res
rdfs:subClassOf
Domains and ranges of properties are specified as RDA entities
RDA unconstrained properties do not specify domain or range
Definition terms are given “in the vernacular”: no special meaning is intended for “resource” or “agent”.
RDA
unconstrained
(not LRM)
RDA
property
rdfs:subPropertyOf

7. IFLA LRM and RDA entities
Super-class of all RDA entities
IFLA LRM and RDA entities
Res
is sub-class of
RDA
Entity
has appellation
Nomen
Work
is created by
Place
Expression
Agent
is associated with
Manifestation
is sub-class of
is modified by
Timespan
Item
Collective
Agent
Person
LRM relationship refined as RDA element sub-type (RDF sub-property)
Family
Corporate Body

8. (Literal/string range) (specific/thing range)
Ontology representation
Canonical property
(no range)
is sub-property of
Datatype property
(Literal/string range)
Object property
(specific/thing range)
Unstructured description
Structured description with associated string/syntax encoding scheme
Identifier with associated string/syntax encoding scheme
Range = RDA entity for IRI of instance of related entity
Range = VES class for IRI of concept from vocabulary encoding scheme
Each type of property is in a separate element set with shared local identification (URI part)

9. Extending/refining RDA
RDA property
Alternative label
Narrower property
Element
RDA class
Narrower class
Entity
RDA Vocabulary
RDA Term/Concept
Alternate label
Narrower term
Alternative vocabulary
Value

10. Linking RDA data
RDA uses RDF maps to link RDA entities, elements, and terms to external vocabularies
Map = set of mappings between source and target elements, etc.
Usually published in Terse Triple Language or N-triple serializations
If there is no target representation in RDF,
“map” is published as an alignment (data crosswalk, not linked data)

11. Thank you! rscchair@rdatoolkit.org