RML Mapper for array of array in json

[chiarisilver]

Hi,
I'm trying to map this json file to RDF, but I probably can not iterate correctly to get the values ​​of "value", which are inside the measures array.

Json:

{ "status": 0, "body": { "updatetime": 1528904042, "timezone": "Europe\/Rome", "measuregrps": [{ "grpid": 1154218424, "attrib": 2, "date": 1528902698, "category": 1, "brand": 1, "modified": 1528902700, "deviceid": null, "measures": [{ "value": 7000, "type": 11, "unit": -2, "algo": 0, "fw": 0, "fm": 131 }] }, { "grpid": 1154218987, "attrib": 2, "date": 1528902745, "category": 1, "brand": 1, "modified": 1528902747, "deviceid": null, "measures": [{ "value": 7200, "type": 11, "unit": -2, "algo": 0, "fw": 0, "fm": 131 }] } ] } }

RML:
`@prefix rr: http://www.w3.org/ns/r2rml#.
@Prefix rml: http://semweb.mmlab.be/ns/rml# .
@Prefix ql: http://semweb.mmlab.be/ns/ql# .
@Prefix xsd: http://www.w3.org/2001/XMLSchema#.
@Prefix fo: http://purl.org/ifo/#.

MAPPING

<#RestingHeartRate>

rml:logicalSource [
rml:source "provaJson.json";
rml:referenceFormulation ql:JSONPath;
rml:iterator "$.body.measuregrps";
];

rr:subjectMap [
rr:template "http://ifo.com/{grpid}";
rr:class fo:HeartRate;
];

rr:predicateObjectMap [
rr:predicate fo:hasTemporalRelationshipToPhysicalActivity;
rr:objectMap [
rr:constant fo:AtRest;
];
];

rr:predicateObjectMap [
rr:predicate fo:hasMeasure;
rr:objectMap [
rr:parentTriplesMap <#MeasureHeartRate>;
];
].

<#MeasureHeartRate>

rml:logicalSource [
rml:source "provaJson.json";
rml:referenceFormulation ql:JSONPath;
rml:iterator "$.body.measuregrps";
];

rr:subjectMap [
rr:template "http://ifo.com/{grpid}";
rr:class fo:Measure;
rml:iterator "$.body.measuregrps";

];

rr:predicateObjectMap [
rr:predicate fo:hasNumericalValue;
rr:objectMap [
rml:reference "@.measures.value";
rr:datatype xsd:float;
];
];

rr:predicateObjectMap [
rr:predicate fo:hasDescriptiveStatistic;
rr:objectMap [
rr:constant fo:average;
];
];

rr:predicateObjectMap [
rr:predicate fo:hasUnit;
rr:objectMap [
rr:constant fo:bpm;
];
].

`

Thanks,
Chiara

[bjdmeest]

Using the JSONPath below gives me access to the values of the value-key, so it should be possible to get the values within a mapping document

$.body.measuregrps[*].measures[*].value

[chiarisilver]

Thank you! But I don't understand which iterator I should assign that path.
Thank's!

[chiarisilver]

Unfortunately it doesn't work..

[canarvaeza]

Hi Chiara, Whats actual output?, the problem is only with *value* or also with others like *fm.* 1) I don´t know if you can say this rr:subjectMap [ rr:template "http://ifo.com/{grpid}"; rr:class fo:Measure; rml:iterator "$.measures"; ]; I have seen the iterator only in the* rml:logicalSource* part. 2) I don't know why you use @ at the path rr:predicateObjectMap [ rr:predicate fo:hasNumericalValue; rr:objectMap [ rml:reference "*@.value*"; rr:datatype xsd:float; ]; ]; Try without @.value, only use value since <#MeasureHeartRate> rml:logicalSource [ rml:iterator "$.body.measuregrps[*].measures[*]" ] Will set the dir to the measures and then you can acces value without problems. Try this command $.body.measuregrps[*].measures[*].value on http://jsonpath.com/ with your json and make some tests. Best, 2018-06-14 8:34 GMT-05:00 chiarisilver <[email protected]>:

…

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-- ------------------------------ Cristian Andres Narvaez Alarcon Estudiante de Maestría en Ingeniería de Sistemas y Computación Universidad Nacional de Colombia