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Change the model

Change the model: create constructors, classes, and constraints

Change the model

In order to be able to manage instances, we need to create classes that represent them in the model of our dataspace. Not only will they serve as RDF types of the instances, but will have constructors attached that define the default properties and their (data)types for that class.

Model is managed in the administration application of a dataspace. Head there by clicking the in the action bar and then choosing Administration.

In order to manage the access control, or the model of a dataspace, the agent needs to be a member of the owners group.

We will use the SKOS ontology and its skos:Concept class as an example in this guide.

Create a constructor

We will use the following SPARQL CONSTRUCT query as a constructor for our Concept class and save it in a file under queries/construct-concept.rq.

PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX xsd:  <http://www.w3.org/2001/XMLSchema#>

CONSTRUCT
{
  $this skos:inScheme [ a skos:ConceptScheme ] ;
    skos:topConceptOf [ a skos:ConceptScheme ] ;
    skos:prefLabel [ a xsd:string ] ;
    skos:altLabel [ a xsd:string ] ;
    skos:hiddenLabel [ a xsd:string ] ;
    skos:notation [ a xsd:string ] ;
    skos:note [ a xsd:string ] ;
    skos:changeNote [ a xsd:string ] ;
    skos:definition [ a xsd:string ] ;
    skos:editorialNote [ a xsd:string ] ;
    skos:example [ a xsd:string ] ;
    skos:historyNote [ a xsd:string ] ;
    skos:scopeNote [ a xsd:string ] ;
    skos:semanticRelation [ a skos:Concept ] ;
    skos:broader [ a skos:Concept ] ;
    skos:narrower [ a skos:Concept ] ;
    skos:related [ a skos:Concept ] ;
    skos:broaderTransitive [ a skos:Concept ] ;
    skos:narrowerTransitive [ a skos:Concept ] ;
    skos:mappingRelation [ a skos:Concept ] ;
    skos:broadMatch [ a skos:Concept ] ;
    skos:narrowMatch [ a skos:Concept ] ;
    skos:relatedMatch [ a skos:Concept ] ;
    skos:exactMatch [ a skos:Concept ] ;
    skos:closeMatch [ a skos:Concept ] .
}
WHERE {}

In the administration application, follow these steps:

  1. Click the Create dropdown in the top-left corner
  2. Click on CONSTRUCT in the drop-down list that appears
  3. Switch the Blank node dropdown to URI and enter https://localhost:4443/ns#ConstructConcept
  4. Fill out the mandatory fields in the form:
    Label
    Enter Construct concept
    Select Domain from the list — this is the ontology in which the query is defined
    Text
    Enter the SPARQL CONSTRUCT query string
  5. Click Save
pwd=$(realpath -s $PWD)

pushd . && cd "$SCRIPT_ROOT"/admin/model

./create-construct.sh \
  -b "${base}admin/" \
  -f "$cert_pem_file" \
  -p "$cert_password" \
  --uri "${base}ns#ConstructConcept" \
  --label "Construct concept" \
  --slug construct-concept \
  --query-file "$pwd/queries/construct-concept.rq" \
  "${base}admin/model/ontologies/namespace/"

popd

Follow the same steps for Concept scheme.

Read more about constructors.

Create a constraint

To control data quality, we probably want to make some of the instance properties mandatory. For example, a skos:Concept instance should always have a skos:prefLabel value.

In the administration application, follow these steps:

  1. Click the Create dropdown in the top-left corner
  2. Click on Missing property value in the drop-down list that appears
  3. Fill out the fields in the form:
    Label
    Enter Missing skos:prefLabel
    IsDefinedBy
    Type Domain into the input (which provides autocomplete)
    Select Domain from the list — this is the ontology in which the query is defined
    Arg1
    Enter http://www.w3.org/2004/02/skos/core#prefLabel
  4. Click Save
pushd . && cd "$SCRIPT_ROOT"/admin/model

./create-property-constraint.sh \
  -b "$base" \
  -f "$cert_pem_file" \
  -p "$cert_password" \
  --uri "https://localhost:4443/ns#MissingPrefLabel" \
  --label "Missing skos:prefLabel" \
  --slug missing-pref-label \
  --property "http://www.w3.org/2004/02/skos/core#prefLabel" \
  "${base}admin/model/ontologies/namespace/"

popd

Read more about constraints.

Create classes

In the administration application, follow these steps to create the concept class:

  1. Click the Create dropdown in the top-left corner
  2. Click on Class in the drop-down list that appears
  3. Switch the Blank node dropdown to URI and enter https://localhost:4443/ns#Concept
  4. Fill out the mandatory fields in the form:
    Label
    Enter Concept
    Select Domain from the list — this is the ontology in which the class is defined
    Constructor
    Type Construct concept into the input (which provides autocomplete)
    Select Construct concept from the list — this is the query we created beforehand
  5. Click Save
pushd . && cd "$SCRIPT_ROOT"/admin/model

./create-class.sh \
  -b "$base" \
  -f "$cert_pem_file" \
  -p "$cert_password" \
  --uri "http://www.w3.org/2004/02/skos/core#Concept" \
  --label "Concept" \
  --slug concept \
  --constructor "{$base}ns#ConstructConcept" \
  --constraint "{$base}ns#MissingPrefLabel" \
  "${base}admin/model/ontologies/namespace/"

popd

Follow the same steps for Concept scheme.

Read more about classes.

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