AttributeError: tripleMap

[MicheleMallia]

Hi,

I am using your library to perform transformations between structured data. I used yatter to do the conversion from yaml to RML, but once I use your library to get the RDF I get this error:

Traceback (most recent call last):
  File "C:\Users\Michele Mallia\Lavoro\H2IOSC\Dev\yarrrml-parser-yatter\script.py", line 16, in <module>
    rdf_graph = rml_converter.convert(rml_file_path)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_mapper.py", line 135, in convert
    triple_mappings = RMLParser.parse(rml_mapping)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_mapper.py", line 47, in parse
    return TripleMappings.from_rdf(g)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 1660, in from_rdf
    return set([TripleMappings.__build(g, row) for row in qres])
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 1660, in <listcomp>
    return set([TripleMappings.__build(g, row) for row in qres])
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 1668, in __build       
    predicate_object_maps = PredicateObjectMap.from_rdf(g, row.tm)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 778, in from_rdf
    return list(map(lmbd(g), qres))
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 777, in <lambda>
    lmbd = lambda graph : lambda row :  PredicateObjectMap.__build(graph, row)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 784, in __build
    predicates = PredicateBuilder.build(g, row.pom)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 695, in build
    predicates += PredicateMap.from_rdf(g, predicate_ref)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\pyrml\pyrml_core.py", line 655, in from_rdf
    pm = PredicateMap(row.tripleMap, row.map, row.termType, row.predicateMap)
  File "C:\Users\Michele Mallia\AppData\Local\Programs\Python\Python39\lib\site-packages\rdflib\query.py", line 124, in __getattr__
    raise AttributeError(name)
AttributeError: tripleMap

This is the structure of RML file:

@prefix ex: <http://example.com/>.
@prefix rr: <http://www.w3.org/ns/r2rml#>.
@prefix rml: <http://semweb.mmlab.be/ns/rml#>.
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix xsd: <http://www.w3.org/2001/XMLSchema#>.
@prefix ql: <http://semweb.mmlab.be/ns/ql#>.
@prefix d2rq: <http://www.wiwiss.fu-berlin.de/suhl/bizer/D2RQ/0.1#>.
@prefix foaf: <http://xmlns.com/foaf/0.1/>.
@prefix schema: <http://schema.org/>.
@prefix formats: <http://www.w3.org/ns/formats/>.
@prefix comp: <http://semweb.mmlab.be/ns/rml-compression#>.
@prefix void: <http://rdfs.org/ns/void#>.
@prefix fnml: <http://semweb.mmlab.be/ns/fnml#>.
@prefix grel: <http://users.ugent.be/~bjdmeest/function/grel.ttl#>.
@base <http://example.com/ns#>.

<person_0> a rr:TriplesMap;

    rml:logicalSource [
        a rml:LogicalSource;
        rml:source "data.json";
        rml:referenceFormulation ql:JSONPath;
        rml:iterator "$.persons[*]";
    ];
    rr:subjectMap [
        a rr:SubjectMap;
        rr:template "http://example.com/{firstname}";
    ];
    rr:predicateObjectMap [
        rr:predicateMap [
            a rr:PredicateMap;
            rr:constant rdf:type;
        ];
        rr:objectMap [
            a rr:ObjectMap;
            rr:constant foaf:Person;
        ];
    ];
    rr:predicateObjectMap [
        rr:predicateMap [
            a rr:PredicateMap;
            rr:constant ex:name;
        ];
        rr:objectMap [
            a rr:ObjectMap;
            rml:reference "firstname";
        ];
    ].

Thank you in advance.

[anuzzolese]

Hi @MicheleMallia,

can you provide me with an example of the JSON file you use as input?

[MicheleMallia]

Hi @anuzzolese,

Thank you for the quick response.

I took my cue from Matey's examples, I was currently doing a simple test with the “people” example, which has a data.json file that has this structure:

{
    "persons": [
        {
            "firstname": "John",
            "lastname": "Doe"
        },
        {
            "firstname": "Jane",
            "lastname": "Smith"
        },
        {
            "firstname": "Sarah",
            "lastname": "Bladinck"
        }
    ]
}

And a mapping file that has this structure:

prefixes:
 ex: "http://example.com/"

mappings:
  person:
    sources:
      - ['data.json~jsonpath', '$.persons[*]']
    s: http://example.com/$(firstname)
    po:
      - [a, foaf:Person]
      - [ex:name, $(firstname)]

[MicheleMallia]

I use Python 3.10