加入多个2+节点/ RMLRDF映射语言中的多跳映射

如何解决加入多个2+节点/ RMLRDF映射语言中的多跳映射

我正在尝试将XML源映射到RDF，但似乎无法使多跳映射或多联接条件起作用。在经历了documentation，examples和test cases之后，我不确定这是否可能。

感谢您为解决该问题提供的帮助。

下面是一个简化的示例XML，我到目前为止创建的rml映射，使用RMLMapper生成的当前RDF输出以及我期望的RDF输出。

数据

<Root>
    <MainNode>
        <name>main1</name>
    </MainNode>
    <OtherNode>
        <name>other1</name>
        <otherCondition>main1</otherCondition>
    </OtherNode>
    <OtherNode>
        <name>other2</name>
        <otherCondition>otherCond2</otherCondition>
    </OtherNode>
    <AnotherNode>
        <name>another1</name>
        <description>anotherDesc1</description>
        <anotherCondition>other1</anotherCondition>
    </AnotherNode>
    <AnotherNode>
        <name>another2</name>
        <description>anotherDesc2</description>
        <anotherCondition>anotherCond2</anotherCondition>
    </AnotherNode>
</Root>

制图

@prefix rml: <http://semweb.mmlab.be/ns/rml#> .
@prefix rr: <http://www.w3.org/ns/r2rml#> .
@prefix ql: <http://semweb.mmlab.be/ns/ql#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-Syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

@prefix testont: <http://www.example.com/ontology/> .
@prefix : <http://www.example.com/rules/> .
@base <http://www.example.com/instance/> .


:TriplesMapAnotherNode a rr:TriplesMap;
  rml:logicalSource [
    rml:source "multihop_data.xml";
    rml:referenceFormulation ql:XPath;
    rml:iterator "//AnotherNode"
  ].

:TriplesMapAnotherNode rr:subjectMap [
  rr:template "{description}"
].

:TriplesMapOtherNode a rr:TriplesMap;
    rml:logicalSource [
        rml:source "multihop_data.xml";
        rml:referenceFormulation ql:XPath;
        rml:iterator "//OtherNode"
    ].

:TriplesMapOtherNode rr:subjectMap [
    rr:template "{name}"
].

:TriplesMapMainNode a rr:TriplesMap;
    rml:logicalSource [
        rml:source "multihop_data.xml";
        rml:referenceFormulation ql:XPath;
        rml:iterator "//MainNode"
    ].

:TriplesMapMainNode rr:subjectMap [
    rr:template "{name}"
].

:TriplesMapMainNode rr:predicateObjectMap [
    rr:predicate rdf:type;
    rr:object testont:MainClass
].

:TriplesMapOtherNode rr:predicateObjectMap [
  rr:predicate testont:dummypredicate;
  rr:objectMap [
    a rr:RefObjectMap;
    rr:parentTriplesMap :TriplesMapAnotherNode;
    rr:joinCondition [
      rr:child "name";
      rr:parent "anotherCondition";
    ]
  ]
].

:TriplesMapMainNode rr:predicateObjectMap [
    rr:predicate testont:hasDescription;
    rr:objectMap [
        a rr:RefObjectMap;
        rr:parentTriplesMap :TriplesMapOtherNode;
        rr:joinCondition [
          rr:child "name";
          rr:parent "otherCondition";
        ]
    ]
].

当前的RDF

<http://www.example.com/instance/other1> <http://www.example.com/ontology/dummypredicate> <anotherDesc1>.
<http://www.example.com/instance/main1> <http://www.example.com/ontology/hasDescription> <other1>.
<http://www.example.com/instance/main1> <http://www.w3.org/1999/02/22-rdf-Syntax-ns#type> <http://www.example.com/ontology/MainClass>.

预期的RDF

<http://www.example.com/instance/main1> <http://www.example.com/ontology/hasDescription> <anotherDesc1>.
<http://www.example.com/instance/main1> <http://www.w3.org/1999/02/22-rdf-Syntax-ns#type> <http://www.example.com/ontology/MainClass>.

简而言之，

• 如何基于2个加入条件加入3个节点？
• 如何跳过或避免创建三元组？
• 我可以根据2个以上的加入条件将其扩展为加入3个以上的节点吗？

谢谢！