modified void:target domain
description: The void:target property domain was modified in voidext schema to be the union of the classes: void:Linkset, and voidext:SharedInstanceSet instead of only the void:Linkset class from the original VoID vocabulary.
issued: 2019-06-30
type: Provenance Statement
creator: Tarcisio Mendes de Farias

number of triples
creator: Keith Alexander
comment: The total number of triples contained in a void:Dataset.
creator: Richard Cyganiak
range: integer
creator: Michael Hausenblas
type: DatatypeProperty
type: Property
creator: Jun Zhao
domain: dataset

vocabulary
domain: dataset
type: Property
creator: Richard Cyganiak
creator: Keith Alexander
creator: Jun Zhao
creator: Michael Hausenblas
comment: A vocabulary that is used in the dataset.

feature
domain: dataset
creator: Michael Hausenblas
creator: Richard Cyganiak
creator: Keith Alexander
range: technical feature
creator: Jun Zhao
type: Property

query for shared instance set
comment: This property must only assign one standard SPARQL query per category (i.e. subclass) of VirtualLinkSet to retrieve the formal definition of shared instance set (i.e. query projection) as presented in the voidext specification.
type: Property
type: AnnotationProperty
range: Literal

classes
creator: Michael Hausenblas
creator: Keith Alexander
type: DatatypeProperty
comment: The total number of distinct classes in a void:Dataset. In other words, the number of distinct resources occuring as objects of rdf:type triples in the dataset.
range: integer
creator: Jun Zhao
domain: dataset
type: Property
creator: Richard Cyganiak

linkset
creator: Michael Hausenblas
creator: Keith Alexander
created: 2010-01-26
comment: A collection of RDF links between two void:Datasets.
type: Class
creator: Jun Zhao
subclass of: dataset
creator: Richard Cyganiak

has subset
range: dataset
creator: Keith Alexander
type: Property
creator: Jun Zhao
creator: Michael Hausenblas
creator: Richard Cyganiak
domain: dataset

Extended Vocabulary of Interlinked Datasets (VoIDext)
type: Ontology
publisher: SIB Swiss Institute of Bioinformatics
is version of: void.ttl
preferred namespace prefix: voidext
license: https://creativecommons.org/licenses/by/3.0/
modified: 2019-06-30
description: The Extension of the Vocabulary of Interlinked Datasets (VoID) RDF Schema that includes the concept of virtual links. This extension enhances interoperability among heterogeneous and distributed RDF data sets by bridging them through explicitly defined virtual links.
creator: Tarcisio Mendes de Farias
created: 2019-01-30
preferred namespace uri: http://purl.org/query/voidext#

has a SPARQL endpoint at
creator: Michael Hausenblas
creator: Keith Alexander
creator: Jun Zhao
type: Property
creator: Richard Cyganiak
domain: dataset

URI space
creator: Richard Cyganiak
creator: Michael Hausenblas
comment: A URI that is a common string prefix of all the entity URIs in a void:Dataset.
range: Literal
domain: dataset
type: Property
type: DatatypeProperty
creator: Jun Zhao
creator: Keith Alexander

number of entities
creator: Keith Alexander
range: integer
comment: The total number of entities that are described in a void:Dataset.
type: DatatypeProperty
creator: Jun Zhao
creator: Michael Hausenblas
type: Property
creator: Richard Cyganiak
domain: dataset

link predicate range
domain: linkset
comment: The link predicate's object type (i.e. class), if any. Moreover, in the case of a void:Linkset that is not classified as a simple link set, if the two datasets are linked through the link predicate's object then the link predicate range must be specified. Indeed, this object matches a second resource in an external dataset. Therefore, the type of this second resource is asserted as the link predicate range.
type: Property
range: Class

Linkset intersection
type: Class
comment: The possible intersection types between the RDF graph nodes in different void:Dataset(s) (i.e. either the subject or the object node of a link predicate). The instances of this class are exclusively voidext:OBJECT_OBJECT, voidext:OBJECT_SUBJECT, and voidext:SUBJECT_SUBJECT.

has URI regular expression pattern
creator: Jun Zhao
creator: Michael Hausenblas
domain: dataset
type: Property
creator: Richard Cyganiak
creator: Keith Alexander
comment: Defines a regular expression pattern matching URIs in the dataset.

Department of Zoology, University of Oxford
member: Jun Zhao
type: Agent

distinct subjects
creator: Michael Hausenblas
type: DatatypeProperty
comment: The total number of distinct subjects in a void:Dataset. In other words, the number of distinct resources that occur in the subject position of triples in the dataset.
type: Property
creator: Richard Cyganiak
domain: dataset
range: integer
creator: Jun Zhao
creator: Keith Alexander

Keith Alexander
type: Person

Tarcisio Mendes de Farias
type: Person

distinct objects
type: Property
type: DatatypeProperty
creator: Richard Cyganiak
creator: Keith Alexander
comment: The total number of distinct objects in a void:Dataset. In other words, the number of distinct resources that occur in the object position of triples in the dataset. Literals are included in this count.
domain: dataset
creator: Michael Hausenblas
range: integer
creator: Jun Zhao

resource mapped with
type: Property
type: DatatypeProperty
range: Literal
type: FunctionalProperty
description: Example of a value assigned with this property is the following "?objectsTarget a <urn:Example>. BIND(IF(contains(?objectsTarget, "Example:" ), IRI(concat("http://example.org/uniprot:",strafter(?objectsTarget,"Example:"))), ?objectsTargetConverted) as ?converted_object) FILTER(BOUND(?obj_converted))". This will convert strings that contains "Example:" into IRIs defined in http://example.org/ namespace.
comment: The preprocessing of a resource (i.e. IRI or literal) in a source void:Dataset in order to match another resource in the target void:Dataset. A resource is either the subject or the object of an RDF triple. The resource preprocessing (i.e. the resource mapping) must be defined with the SPARQL language by mainly using SPARQL built-ins for assignments (e.g. BIND), and expression and testing values (e.g. IF and FILTER). BIND is used to assign the output of a function.
domain: LINK SHAREDINSTANCE SET

dataset description
creator: Keith Alexander
subclass of: Document
comment: A web resource whose foaf:primaryTopic or foaf:topics include void:Datasets.
creator: Jun Zhao
type: Class
creator: Michael Hausenblas
creator: Richard Cyganiak

Subject-subject intersection
type: Linkset intersection
comment: The intersection between two void:Dataset(s) (i.e. knowledge graphs) occurs at the subject node in both datasets.

SIB Swiss Institute of Bioinformatics
member: Tarcisio Mendes de Farias
type: Agent

number of documents
domain: dataset
creator: Richard Cyganiak
creator: Jun Zhao
range: integer
creator: Keith Alexander
type: Property
type: DatatypeProperty
creator: Michael Hausenblas
comment: The total number of documents, for datasets that are published as a set of individual documents, such as RDF/XML documents or RDFa-annotated web pages. Non-RDF documents, such as web pages in HTML or images, are usually not included in this count. This property is intended for datasets where the total number of triples or entities is hard to determine. void:triples or void:entities should be preferred where practical.

Provenance Statement
type: Class

Objects Target
comment: The dataset describing the objects of the triples contained in the Linkset.
domain: linkset
creator: Richard Cyganiak
creator: Keith Alexander
creator: Michael Hausenblas
creator: Jun Zhao
type: FunctionalProperty
sub property of: Target
type: Property
created: 2010-01-26
range: dataset

technical feature
creator: Richard Cyganiak
creator: Keith Alexander
type: Class
comment: A technical feature of a void:Dataset, such as a supported RDF serialization format.
creator: Jun Zhao
creator: Michael Hausenblas

Target
creator: Jun Zhao
creator: Michael Hausenblas
creator: Richard Cyganiak
range: dataset
type: Property
modified: 2019-06-30
provenance: modified void:target domain
comment: One of the two datasets linked by the Linkset or the Shared instance set.
created: 2010-01-26
creator: Keith Alexander
domain: LINK SHAREDINSTANCE SET
contributor: Tarcisio Mendes de Farias

LiDRC
member: Michael Hausenblas
type: Agent

intersects at
type: ObjectProperty
comment: This property is used to assign exactly either two shared instance sets (voidext:SharedInstanceSet) or two link sets (void:Linkset) to compose a complex link set (voidext:ComplexLinkSet). For each void:Linkset, either the subject or the object node of its link predicate intersects an RDF node of the link predicate from the other link set. In other words, the subject xor the object of a link predicate matches the subject xor the object of the other link predicate, where xor is the exclusive or. These link predicates must be from different datasets.
range: LINK SHAREDINSTANCE SET
type: Property
domain: Complex link set

example resource of dataset
creator: Jun Zhao
creator: Michael Hausenblas
type: Property
creator: Keith Alexander
range: Resource
creator: Richard Cyganiak
domain: dataset

link predicate domain
comment: The link predicate's subject type (i.e. class), if any. Moreover, in the case of a void:Linkset that is classified as a simple link set (voidext:SimpleLinkSet), if the two datasets are linked through the link predicate's subject then the link predicate domain must be specified. Indeed, this subject matches a second resource in an external dataset. Therefore, the type of this second resource is asserted as the link predicate domain.
range: Class
domain: linkset
type: Property

property partition
domain: dataset
range: dataset
creator: Jun Zhao
creator: Michael Hausenblas
creator: Richard Cyganiak
type: Property
creator: Keith Alexander
comment: A subset of a void:Dataset that contains only the triples of a certain rdf:Property.
sub property of: has subset

Richard Cyganiak
type: Person

Complex link set
query for linkset: prefix void: <http://rdfs.org/ns/void#> prefix voidext:<http://purl.org/query/voidext#> prefix dcterms: <http://purl.org/dc/terms/> SELECT distinct ?links ?source_dataset1_name ?target_dataset2_name ?predicate ?intersection_type ?subj_type ?obj_type ?source_endpoint ?target_endpoint ?resourceMapping { #values(?dataset1){ (bioquery:EBI_ORDO) } #values(?dataset2){ (bioquery:DRUGBANK) } ?links a voidext:ComplexLinkSet. ?links voidext:intersectAt ?set2; voidext:intersectionType/rdfs:label ?intersection_type. ?set2 voidext:isSubsetOf ?target_db. ?target_db dcterms:title ?target_dataset2_name; void:sparqlEndpoint ?target_endpoint. ?set2 void:linkPredicate ?predicate2 . ?links voidext:intersectAt ?set1. ?set1 void:linkPredicate ?predicate . ?set1 voidext:isSubsetOf ?source_db . ?source_db dcterms:title ?source_dataset1_name; void:sparqlEndpoint ?source_endpoint. optional{ ?set1 voidext:linkPredicateDomain ?subj_type} optional{ ?set1 voidext:linkPredicateRange ?obj_type.} optional{ ?links voidext:recommendedMapping ?set1. ?set1 voidext:resourceMapping ?resourceMapping} filter(?source_db != ?target_db) } order by ?links
type: Class
query for shared instance set: prefix void: <http://rdfs.org/ns/void#> prefix voidext:<http://purl.org/query/voidext#> prefix dcterms: <http://purl.org/dc/terms/> SELECT distinct ?links ?source_dataset1_name ?target_dataset2_name ?sharedType ?resourceMapping ?source_endpoint ?target_endpoint{ #values(?source_db){ (bioquery:EBI) } #values(?target_db){ (bioquery:UNIPROT) } ?links a voidext:ComplexLinkSet. ?links voidext:intersectAt ?set1; voidext:intersectAt ?set2. ?set1 voidext:isSubsetOf ?target_db. ?target_db dcterms:title ?target_dataset2_name; void:sparqlEndpoint ?target_endpoint. ?set2 voidext:sharedInstanceType ?sharedType . ?set2 voidext:isSubsetOf ?source_db . ?source_db dcterms:title ?source_dataset1_name; void:sparqlEndpoint ?source_endpoint. optional{ ?links voidext:recommendedMapping ?set2. ?set2 voidext:resourceMapping ?resourceMapping} filter(?target_db != ?source_db) } order by ?links
equivalent class: Class
  intersection of: Class
    union of: Restriction
      on property: intersects at
      on class: Shared instance set
      qualified cardinality: 2
    union of: Restriction
      on class: linkset
      on property: intersects at
      qualified cardinality: 2
  intersection of: Class
    complement of: Simple link set
comment: It is a complex virtual link set. A complex link set is composed of exactly two link sets xor two shared instance sets where xor is the exclusive or. For example, two link sets that intersects at some graph node (e.g. the object nodes of link predicates).
disjoint with: dataset
subclass of: Virtual link set

Shared instance set
subclass of: dataset
type: Class
comment: A shared instance set between exactly two datasets. For example, two datasets that contain the same OWL/RDFS class instances.

number of properties
creator: Michael Hausenblas
type: DatatypeProperty
comment: The total number of distinct properties in a void:Dataset. In other words, the number of distinct resources that occur in the predicate position of triples in the dataset.
domain: dataset
range: integer
creator: Jun Zhao
type: Property
creator: Richard Cyganiak
creator: Keith Alexander

shared instance type
type: Property
comment: This property assings the type (i.e. class) of the shared instances from a given void:Dataset. Shared instances implies equivalent or similar instance IRIs that belong to different datasets.
range: Class
domain: Shared instance set

Virtual link set
type: Class
comment: A set of virtual links between two datasets. A virtual link is a connection between resources such as literals and instances with some commonality. Each of these resources is from a different RDF dataset. A resource mapping can be also considered when defining common resources between datasets. For example, the datasets uses different prefix namespaces for similar instances in a given domain scope. A virtual link can be interpreted as an intersection data point between two datasets. In addition, a virtual link is not concretely stored. The link may be physically established during a federated query execution, for example. This class must only have instances of its subclasses. It is recommendable to comment (rdfs:comment) the scope of the virtual link set.

Subjects Target
sub property of: Target
creator: Michael Hausenblas
created: 2010-01-26
creator: Richard Cyganiak
creator: Keith Alexander
type: Property
range: dataset
comment: The dataset describing the subjects of triples contained in the Linkset.
type: FunctionalProperty
domain: linkset
creator: Jun Zhao

property
creator: Keith Alexander
domain: dataset
comment: The rdf:Property that is the predicate of all triples in a property-based partition.
creator: Richard Cyganiak
type: FunctionalProperty
creator: Michael Hausenblas
creator: Jun Zhao
range: Property
type: Property

dataset
creator: Michael Hausenblas
type: Class
creator: Keith Alexander
creator: Richard Cyganiak
comment: A set of RDF triples that are published, maintained or aggregated by a single provider.
creator: Jun Zhao

query for linkset
type: AnnotationProperty
type: Property
comment: This property must only assign one standard SPARQL query per category (i.e. subclass) of VirtualLinkSet to retrieve the formal definition of linkset (i.e. query projection) as presented in the voidext specification.
range: Literal

intersection type
comment: This property assigns the intersection type of two RDF triples in different datasets (void:Dataset). In other words, if the intersection occurs at the subject xor the object node of a link predicate.
type: ObjectProperty
type: Property
range: Linkset intersection
domain: Complex link set

Object-object intersection
comment: The intersection between two void:Dataset(s) (i.e. knowledge graphs) occurs at the object node in both datasets.
type: Linkset intersection

open search description
creator: Michael Hausenblas
comment: An OpenSearch description document for a free-text search service over a void:Dataset.
creator: Richard Cyganiak
range: Document
creator: Jun Zhao
type: Property
creator: Keith Alexander
domain: dataset

Jun Zhao
type: Person

class
domain: dataset
type: FunctionalProperty
creator: Michael Hausenblas
creator: Keith Alexander
creator: Richard Cyganiak
creator: Jun Zhao
comment: The rdfs:Class that is the rdf:type of all entities in a class-based partition.
range: Class
type: Property

recommended mapping from
type: ObjectProperty
type: FunctionalProperty
range: LINK SHAREDINSTANCE SET
comment: If more than one mapping is defined in the different void:Linkset(s) that are part of a voidext:ComplexLinkSet, one of the resource mappings may be recommended by asserting this property. The recommended mapping is the one stated to the void:Linkset assigned as the value of this property. If no mapping is explicitly recommended, solely one of them must arbitrarily be applied to establish a virtual link. At most one mapping function can be defined either per linkset or per shared instance set.
domain: Complex link set
type: Property

has an URI look-up endpoint at
creator: Richard Cyganiak
domain: dataset
comment: Defines a simple URI look-up protocol for accessing a dataset.
creator: Jun Zhao
creator: Michael Hausenblas
type: Property
creator: Keith Alexander

class partition
creator: Keith Alexander
creator: Michael Hausenblas
creator: Jun Zhao
comment: A subset of a void:Dataset that contains only the entities of a certain rdfs:Class.
type: Property
range: dataset
creator: Richard Cyganiak
sub property of: has subset
domain: dataset

a link predicate
creator: Michael Hausenblas
creator: Jun Zhao
creator: Richard Cyganiak
range: Property
domain: linkset
type: Property
creator: Keith Alexander
comment: It specifies the RDF predicate in a given dataset that relates to another dataset. In other words, the link predicate is the RDF property in the predicate position of an RDF triple that links two datasets.

Simple link set
type: Class
comment: A simple link set must be a linkset that does not target another linkset (i.e. it has exactly one link predicate) or a set with exactly the same shared instances of the same type (i.e. class) in both datasets. The instances of this class must be also instances of either void:Linkset or voidext:SharedInstanceSet.
subclass of: Virtual link set
equivalent class: Class
  union of: Class
    intersection of: Shared instance set
    intersection of: Class
      complement of: Restriction
        on property: is subset of
        on class: dataset
        qualified cardinality: 1
  union of: Class
    intersection of: linkset
    intersection of: Class
      complement of: Restriction
        on property: Target
        some values from: linkset
query for linkset: prefix void: <http://rdfs.org/ns/void#> prefix voidext:<http://purl.org/query/voidext#> prefix dcterms: <http://purl.org/dc/terms/> SELECT distinct ?links ?source ?predicate_from_endpoint ?subj_from ?subj_type ?predicate ?obj_type ?obj_from ?resourceMapping { ###if we want to specify the target datasets that contain one of the resources ###related with a virtual link. #values(?dataset_link_subj){ (bioquery:OMA) } #values(?dataset_link_obj){ (bioquery:UNIPROT) } ?links a void:Linkset. { ?links void:subjectsTarget ?dataset_link_subj . ?links void:objectsTarget ?dataset_link_obj. } UNION { ?links void:target ?dataset_link_subj. ?links void:target ?dataset_link_obj .} ?links void:linkPredicate ?predicate; voidext:isSubsetOf ?source_db. ?dataset_link_subj void:sparqlEndpoint ?subj_from. ?dataset_link_obj void:sparqlEndpoint ?obj_from. ?source_db dcterms:title ?source; void:sparqlEndpoint ?predicate_from_endpoint. optional {?links voidext:linkPredicateRange ?obj_type}. optional {?links voidext:linkPredicateDomain ?subj_type. } optional{ ?links voidext:resourceMapping ?resourceMapping} filter not exists { ?complexLink voidext:intersectAt ?links.} filter ( ?dataset_link_subj != ?dataset_link_obj ) } order by ?links
query for shared instance set: prefix void: <http://rdfs.org/ns/void#> prefix voidext:<http://purl.org/query/voidext#> prefix dcterms: <http://purl.org/dc/terms/> SELECT distinct ?links ?dataset1_name ?dataset2_name ?sharedType ?dataset1_endpoint ?dataset2_endpoint { #values(?dataset1){ (bioquery:BGEE) } #values(?dataset2){ (bioquery:OMA) } ?links a voidext:SharedInstanceSet. ?links void:target ?dataset1. ?links void:target ?dataset2. ?links voidext:sharedInstanceType ?sharedType. ?dataset1 dcterms:title ?dataset1_name; void:sparqlEndpoint ?dataset1_endpoint. ?dataset2 dcterms:title ?dataset2_name; void:sparqlEndpoint ?dataset2_endpoint. filter not exists { ?complexLink voidext:intersectAt ?links .} filter(?dataset1 != ?dataset2) } order by ?links

Talis
type: Agent
member: Keith Alexander

root resource
creator: Keith Alexander
domain: dataset
comment: A top concept or entry point for a void:Dataset that is structured in a tree-like fashion. All resources in a dataset can be reached by following links from its root resources in a small number of steps.
creator: Richard Cyganiak
type: Property
creator: Michael Hausenblas
creator: Jun Zhao

Digital Enterprise Research Institute, NUI Galway
type: Agent
member: Richard Cyganiak

Data Dump
creator: Michael Hausenblas
range: Resource
creator: Keith Alexander
domain: dataset
type: Property
creator: Richard Cyganiak
creator: Jun Zhao
comment: An RDF dump, partial or complete, of a void:Dataset.

is subset of
range: dataset
type: ObjectProperty
domain: dataset
inverse of: has subset
type: Property

supports SPARQL 1.1 federated query
domain: dataset
range: boolean
comment: This property should be used to explicitly assert that a void:Dataset supports SPARQL 1.1. federated queries to be able to access the dataset with the SERVICE keyword and perform federated join queries.
type: DatatypeProperty
type: Property

in dataset
creator: Richard Cyganiak
domain: Document
type: Property
creator: Michael Hausenblas
creator: Jun Zhao
creator: Keith Alexander
range: dataset
comment: Points to the void:Dataset that a document is a part of.

Michael Hausenblas
type: Person

Subject-object intersection
type: Linkset intersection
comment: The intersection between two void:Dataset(s) (i.e. knowledge graphs) occurs at the object node of one data set (graph) and the subject node of another data set (graph).

has performance measure
type: Property
type: ObjectProperty
domain: Virtual link set
comment: This property assings the performance of the virtual link set, for example, in terms of recall and precision. The values to be assigned (property range) are represented with the ontology MEX Performance Ontology.
range: PerformanceMeasure