sparql - 如何通过多个实体进行查询？

Question

我有一个rdf-schema和turtle语法中的三元组（提取）：

@prefix dbr: <http://dbpedia.org/resource/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

#own, TODO change it
@prefix japany: <http://vschuberth.bplaced.net/rdfschema.ttl#> .

japany:import a rdfs:Class.
japany:food a rdfs:Class.
japany:radioactiveIngredients a rdfs:Class.

japany:imports a rdf:Property;
    rdfs:range dbr:PopulatedPlace;
    rdfs:domain japany:import.

japany:exports a rdf:Property;
    rdfs:range dbr:PopulatedPlace;
    rdfs:domain japany:import.

japany:importQuantity a rdf:Property;
    rdfs:range xsd:integer;
    rdfs:domain japany:import.

japany:importValue a rdf:Property;
    rdfs:range xsd:integer;
    rdfs:domain japany:import.

japany:year a rdf:Property;
    rdfs:range xsd:gYear;
    rdfs:domain japany:import.

japany:isPartOf a rdf:Property;
    rdfs:range japany:import;
    rdfs:domain japany:food.

japany:nameOfIng a rdf:Property;
    rdfs:range rdf:Class;
    rdfs:domain japany:radioactiveIngredients.

japany:amount a rdf:Property;
    rdfs:range japany:bqkg;
    rdfs:domain japany:radioactiveIngredients.

japany:nameOfFood a rdf:Property;
    rdfs:range rdf:Class;
    rdfs:domain japany:food.

japany:dateOfSampling a rdf:Property;
    rdfs:range xsd:date;
    rdfs:domain japany:radioactiveIngredients.

japany:isIn a rdf:Property;
    rdfs:range xsd:food;
    rdfs:domain japany:radioactiveIngredients.

<#Import_of_Olivenöl>
japany:imports dbr:Germany;
japany:exports dbr:Japan;
japany:importQuantity 0;
japany:importValue 36;
japany:year "2011"^^xsd:gYear.

<#Olivenöl_Class>
japany:isPartOf <#Import_of_Olivenöl>.

<#Iodine131_in_Olivenöl>
japany:nameOfIng "Iodine131";
japany:amount "< 2,3";
japany:nameOfFood "Olivenöl";
japany:dateOfSampling "15.04.2011"^^xsd:date;
japany:isIn <#Import_of_Olivenöl>.

<#Cesium134_in_Olivenöl>
japany:nameOfIng "Caesium134";
japany:amount "< 1,54";
japany:nameOfFood "Olivenöl";
japany:dateOfSampling "15.04.2011"^^xsd:date;
japany:isIn <#Import_of_Olivenöl>.

<#Cesium137_in_Olivenöl>
japany:nameOfIng "Caesium137";
japany:amount "< 1,95";
japany:nameOfFood "Olivenöl";
japany:dateOfSampling "15.04.2011"^^xsd:date;
japany:isIn <#Import_of_Olivenöl>.

我很困惑如何查询所有这些实体。他们彼此相关。例如：我想编写一个查询/查询来获取每年每种食物的importValue和importQuantity，并列出每个放射性成分的含量。

这个查询会给我不正确的数据：

PREFIX japany: <http://vschuberth.bplaced.net/rdfschema.ttl#>


SELECT ?importValue ?importQuantity ?name ?year
WHERE {
  ?trade japany:importValue ?importValue;
         japany:year ?year;
  japany:importQuantity ?importQuantity.
  ?food japany:nameOfFood ?name.

}
ORDER BY ?importQuantity

任何人都可以帮忙吗？

Answer 1

问题是?food和japany:import在您的查询中没有链接。

这是一个有效的查询：

PREFIX japany: <http://vschuberth.bplaced.net/rdfschema.ttl#>

SELECT ?importValue ?importQuantity ?name ?year
WHERE {
  ?food japany:isPartOf ?import .
  ?import japany:importValue ?importValue ;
                japany:importQuantity ?importQuantity ;
                japany:year ?year .
  ?food japany:nameOfFood ?name.
}
ORDER BY ?importQuantity

但这令人毛骨悚然：

japany:nameOfFood a rdf:Property;
    rdfs:range rdf:Class.

你为什么不创建它作为DatatypeProperty，因此存储Literal？