Identifier
Identifier Proposal
Status: Draft
Author: Richard Wallis
Overview
There is a need for associating standard identifiers of many types with bibliographic resources, authors and organisations. The Schema.org BookType has an isbn property which satisfies the need for the most commonly used identifier. It would not be practical to expand this approach for all identifier types.
It is proposed to define a new Identifier Type to describe the value, type, issuing authority, etc. of an identifier. It is further proposed to add an identifier property to the CreativeWork, Organization and Person types with an expected type of Identifier.
Implementation Note: It is recognised that not all standard identifier issuing organisations will be in a position to publish such rich metadata for some time. The identifier property can therefore be expected to contain an Identifier Type, URI identifier, URN, or text identifier.
Expansion Note: The issue of many identifier types is not constrained to the bibliographic domain. It is therefore proposed to suggested the addition of an identifier property to the Thing type allowing the benefit across all Schema.org types.
Proposal
1. Add one new Type:
Identifier, inherited from Intangible.
Definition: "An intangible item that describes a standard identifier"
| Properties from Identifier | ||
| name | Text | The value of the identifier. |
| inStandard | Text | The standard that defines the identifier. e.g.. ISBN, ISNI, ISSN |
| issuedBy | schema.org/Organization | The issuing organization. |
| issueDate | Date | Issue date. |
| identifies | schema.org/Thing | Thing this identifier identifies |
2. The addition of one property to one or more types.
2.1. Either:
2.1.1. The addition of one property to the Thing Type
| Property | Expected Type | Description |
| identifier | schema.org/Identifier | Identifier for the Thing Preferred values, in order of preference: Schema.org/Identifier, http URI, URN, Text |
2.2 Or:
2.2.1. The addition of one property to the CreativeWork Type
| Property | Expected Type | Description |
| identifier | schema.org/Identifier | Identifier for the Work Preferred values, in order of preference: Schema.org/Identifier, http URI, URN, Text |
2.2.2. The addition of one property to the PersonType
| Property | Expected Type | Description |
| identifier | schema.org/Identifier | Person Identifier. eg. ISNI, VIAF, Organisational number Preferred values, in order of preference: Schema.org/Identifier, http URI, URN, Text |
2.2.3. The addition of one property to the Organization Type
| Property | Expected Type | Description |
| identifier | schema.org/Identifier | Organization Identifier. eg.OCLC Symbol, ISIL, MARC Organizational Code, IATI ORG Identifier Preferred values, in order of preference: Schema.org/Identifier, http URI, URN, Text |
Model
Examples
Initial example in RDF Turtle format - other formats to follow - RJW
@prefix schema: <http://schema.org/> .
<http://www.worldcat.org/oclc/38264520>
a schema:Book;
schema:isbn "9780553479430";
schema:isbn "0553479431";
schema:identifier <http://bowker.com/identifiers/isbn/9780553479430>;
schema:identifier <urn:nbn:ch:bel-9039>;
schema:name "War and Peace";
schema:about <http://id.loc.gov/authorities/names/n79054933>;
schema:author <http://viaf.org/viaf/96987389>;
schema:author [ a schema:Person;
schema:name "Tolstoy, Leo, graf, 1828-1910."];
schema:inLanguage "en";
schema:genre "History";
schema:genre "Fiction";
schema:description "An epic novel featuring the Russian role in the Napoleonic wars and providing a complex panorama of the life of the time.";
schema:instanceOf <http://exampleworks.org/work/12345>.
<http://bowker.com/identifiers/isbn/9780553479430>
a schema:Identifier;
schema:name "9780553479430";
schema:inStandard "ISBN";
schema:issuedBy <http://viaf.org/viaf/142397918>;
schema:issueDate "1997";
schema:identifies <http://www.worldcat.org/oclc/38264520>.
Note: Bowker URIs for ISBNs does not exist - included to make example more real.
Alternate Proposed based on SKOS
These examples should prove that the patterns above are already handled in SKOS. If we can convince Schema.org to integrate SKOS (which should be tempting for a variety of reasons anyway), then custom classes and properties to handle identifiers aren't necessary.
| Properties from Concept | ||
| prefLabel or possibly just name | Text | The legacy identifier literal. |
| inScheme | ConceptScheme | The "standard" (ISBN, etc.) that coins the identifier |
| focus | schema.org/Thing | The Thing this identifier identifies |
<http://bowker.com/identifiers/isbn/9780553479430>
a skos:Concept;
schema:name "9780553479430";
schema:inScheme <http://bowker.com/concept-scheme/isbn> ;
schema:focus <http://www.worldcat.org/oclc/38264520>.
<http://bowker.com/concept-scheme/isbn>
a skos:ConceptScheme;
schema:name "ISBN Identifier Scheme".
Adopting approach from medical/health extension
The health/medical extensions to schema.org (doc is used for expressing the medical code for an entity in microdata. This doesn't provide us with a full out-of-the-box solution and the naming ('code' vs. 'identifier') might not sound right to some. But, generally, there probably is no significant difference between a code for a disease or a drug and an identifier for a CreativeWork.
It might be a good approach to pick up the medical approach and extend it to other domains than to come up with a new proposal.
Example (from http://schema.org/MedicalGuideline):
<span itemprop="about" itemscope itemtype="http://schema.org/Drug">
<span itemprop="name">Metformin</span>
<span itemprop="code" itemscope
itemtype="http://schema.org/MedicalCode"
itemid="http://www.ncbi.nlm.nih.gov/mesh/D02.078.370.141.450">
<!-- Note: use of itemid is not mandatory, but recommended when an
external enumeration is available -->
<meta itemprop="code" content="D02.078.370.141.450"/>
<meta itemprop="codingSystem" content="MeSH"/>
</span>
More examples at http://schema.org/MedicalCondition , http://schema.org/MedicalScholarlyArticle.
Adoption for bibliographic identifiers (analogous to Richard's examples)
@prefix schema: <http://schema.org/> .
<http://www.worldcat.org/oclc/38264520>
a schema:Book;
schema:gtin13 "9780553479430";
schema:isbn "0553479431";
schema:code [
a schema:Identifier # Would have to be added.
schema:code "38264520";
schema:codingSystem "OCLC number"
] ;
schema:name "War and Peace";
schema:about <http://id.loc.gov/authorities/names/n79054933>;
schema:author <http://viaf.org/viaf/96987389>;
schema:author [ a schema:Person;
schema:name "Tolstoy, Leo, graf, 1828-1910."];
schema:inLanguage "en";
schema:genre "History";
schema:genre "Fiction";
schema:description "An epic novel featuring the Russian role in the Napoleonic wars and providing a complex panorama of the life of the time.";
schema:instanceOf <http://exampleworks.org/work/12345>.
<http://bowker.com/identifiers/isbn/9780553479430>
a schema:Identifier;
schema:code "9780553479430";
schema:codingSystem "ISBN";
schema:publisher <http://viaf.org/viaf/142397918>;
schema:dateCreated "1997";
schema:identifies <http://www.worldcat.org/oclc/38264520> .
What's missing then would be schema:Identifier and schema:identifies. Though I don't know whether you need schema:identifies as you have an inverse property with schema:code.