Fix vocprez queries to support inverse skos relationships

[edmondchuc]

The current set of vocprez queries to provide progressive loading of very large vocabs only supports skos:hasTopConcept and skos:broader relationships. This PR adds support for the same relationships and its inverse relationships, skos:topConceptOf and skos:narrower.

Fixes #162.

[edmondchuc]

A test is skipped because the combination of the data and the generated query results in an exception in RDFLib's SPARQL processor.

Generated query

PREFIX prez: <https://prez.dev/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>

CONSTRUCT {
  ?concept skos:prefLabel ?label .
  ?concept prez:childrenCount ?narrowerChildrenCount .
  ?iri prez:childrenCount ?childrenCount .
  ?iri skos:hasTopConcept ?concept .
  ?iri rdf:type ?type .
  ?concept rdf:type ?conceptType .
}
WHERE {
  BIND(<http://linked.data.gov.au/def2/borehole-purpose-no-children> as ?iri)
  OPTIONAL {
    ?iri skos:hasTopConcept ?concept .
    ?concept skos:prefLabel ?label .
  }
  OPTIONAL {
    ?concept skos:topConceptOf ?iri .
    ?concept skos:prefLabel ?label .
  }
  ?iri rdf:type ?type .
  ?concept rdf:type ?conceptType .

  {
    SELECT (COUNT(?childConcept) AS ?childrenCount)
    WHERE {
      BIND(<http://linked.data.gov.au/def2/borehole-purpose-no-children> as ?iri)
      ?iri skos:hasTopConcept ?childConcept .
    }
  }

  {
    SELECT ?concept ?label (COUNT(?narrowerConcept) AS ?narrowerChildrenCount)
    WHERE {
      BIND(<http://linked.data.gov.au/def2/borehole-purpose-no-children> as ?iri)
      OPTIONAL {
        ?iri skos:hasTopConcept ?concept .
        ?concept skos:prefLabel ?label .
      }
      OPTIONAL {
        ?concept skos:topConceptOf ?iri .
        ?concept skos:prefLabel ?label .
      }

      OPTIONAL {
        ?narrowerConcept skos:broader ?concept .
      }
      OPTIONAL {
        ?concept skos:narrower ?narrowerConcept .
      }
    }
    GROUP BY ?concept ?label
    ORDER BY str(?label)
    LIMIT 20
    OFFSET 0
  }
}

Traceback

Traceback (most recent call last):
  File "/Users/edmondchuc/projects/prez/tests/local_sparql_store/store.py", line 178, in apply_sparql_query
    result = vocprez_graph.query(new_query)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/graph.py", line 1567, in query
    return result(processor.query(query_object, initBindings, initNs, **kwargs))  # type: ignore[arg-type]
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/processor.py", line 140, in query
    return evalQuery(self.graph, query, initBindings, base)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 695, in evalQuery
    return evalPart(ctx, main)
           ^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 323, in evalPart
    return evalConstructQuery(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 597, in evalConstructQuery
    for c in evalPart(ctx, query.p):
             ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 303, in evalPart
    return evalProject(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 561, in evalProject
    res = evalPart(ctx, project.p)
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 288, in evalPart
    return evalJoin(ctx, part)
           ^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 156, in evalJoin
    b = set(evalPart(ctx, join.p2))
            ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 296, in evalPart
    return evalMultiset(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 266, in evalMultiset
    return evalPart(ctx, part.p)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 305, in evalPart
    return evalSlice(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 499, in evalSlice
    res = evalPart(ctx, slice.p)
          ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 303, in evalPart
    return evalProject(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 561, in evalProject
    res = evalPart(ctx, project.p)
          ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 312, in evalPart
    return evalOrderBy(ctx, part)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/edmondchuc/projects/prez/venv/lib/python3.11/site-packages/rdflib/plugins/sparql/evaluate.py", line 491, in evalOrderBy
    res = sorted(
          ^^^^^^^
TypeError: '<' not supported between instances of 'NoneType' and 'NoneType'