2

我有一个 SPARQL 查询：

PREFIX  rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  person: <http://www.myOntDomain/person#>
PREFIX  likedEvent: <http://www.myOntDomain/likedEventRule#>
PREFIX  event: <http://www.myOntDomain/event#>
PREFIX  owl:  <http://www.w3.org/2002/07/owl#>
PREFIX  xsd:  <http://www.w3.org/2001/XMLSchema#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  weather: <http://www.myOntDomain/weather#>
PREFIX  eventHasSuitableWeather: <http://www.myOntDomain/eventHasSuitableWeather#>
PREFIX  freeAtEvent: <http://www.myOntDomain/freeAtEventRule#>

SELECT DISTINCT  ?Event ?Person ?Time
WHERE
  { ?Person   rdf:type              person:Person .
    ?Event    rdf:type              event:Event .
    ?WeatherEvent
              rdf:type              weather:WeatherEvent .
    ?WeatherType  rdf:type          weather:WeatherEventType .
    ?Person   likedEvent:likedEvents  ?Event ;
              freeAtEvent:freeAtEvent  ?Event .
    ?Event    eventHasSuitableWeather:eventHasSuitableWeather  true ;
              event:eventHasDate    ?Time .
    ?Person   person:hasName        ?PersonName ;
              person:hasAge         ?PersonAge .
    ?Event    event:hasEventType    ?EventType .
  }

它返回特定本体的以下结果集：

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Event                                                                   | Person                                            | Time                                                                |
=====================================================================================================================================================================================================
| <http://www.myOntDomain/event#SyntheticPitchFootballMatch> | <http://www.myOntDomain/person#Ali>  | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SerlockHolmesMovie>          | <http://www.myOntDomain/person#Ali>  | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SerlockHolmesMovie>          | <http://www.myOntDomain/person#Ayse> | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SyntheticPitchFootballMatch> | <http://www.myOntDomain/person#Veli> | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/weather#AnkaraMuseumVisit>         | <http://www.myOntDomain/person#Ali>  | "2010-01-19T17:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

我想添加一个时间限制来选择当时将发生的事件：

2010-01-19T16:00:00Z

所以我在我的查询中添加了一个 FILTER 元素，现在是：

PREFIX  rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  person: <http://www.myOntDomain/person#>
PREFIX  likedEvent: <http://www.myOntDomain/likedEventRule#>
PREFIX  event: <http://www.myOntDomain/event#>
PREFIX  owl:  <http://www.w3.org/2002/07/owl#>
PREFIX  xsd:  <http://www.w3.org/2001/XMLSchema#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  weather: <http://www.myOntDomain/weather#>
PREFIX  eventHasSuitableWeather: <http://www.myOntDomain/eventHasSuitableWeather#>
PREFIX  freeAtEvent: <http://www.myOntDomain/freeAtEventRule#>

SELECT DISTINCT  ?Event ?Person ?Time
WHERE
  { ?Person   rdf:type              person:Person .
    ?Event    rdf:type              event:Event .
    ?WeatherEvent
              rdf:type              weather:WeatherEvent .
    ?WeatherType  rdf:type          weather:WeatherEventType .
    ?Person   likedEvent:likedEvents  ?Event ;
              freeAtEvent:freeAtEvent  ?Event .
    ?Event    eventHasSuitableWeather:eventHasSuitableWeather  true ;
              event:eventHasDate    ?Time .
    ?Person   person:hasName        ?PersonName ;
              person:hasAge         ?PersonAge .
    ?Event    event:hasEventType    ?EventType .
    FILTER ( ?Time = "2010-01-19T16:00:00Z"^^xsd:dateTime )
  }

但是，这次查询在同一本体上返回空结果列表：

-------------------------
| Event | Person | Time |
=========================
-------------------------

显然我遗漏了一些关于 SPARQL 或 xsd:dateTime 比较的内容，但我无法弄清楚。如果您有想法，请指导我。谢谢。

更新

我使用 Jena 框架中使用的 SPARQL 的 ARQ 实现。我认为问题在于实现而不是本体或查询

我检查了 com.hp.hpl.jena.datatypes.xsd.XSDDateTime 和 com.hp.hpl.jena.datatypes.xsd.AbstractDateTime 的实现可以在这里找到：http: //grepcode.com/file/repo1.maven .org/maven2/com.hp.hpl.jena/jena/2.6.0/com/hp/hpl/jena/datatypes/xsd

并看到 dateTime 对象由 9 个值表示：

protected final static int CY = 0, M = 1, D = 2, h = 3, m = 4, s = 5, ms = 6, utc=7, msscale=8

当从 java.util.Calendar 对象创建 XSDDateTime 对象并且从本体解析的 XSDDateTime 对象始终为零时，值 msscale 始终为 3。此外，比较函数会检查所有这 9 个值是否相等，因此它们永远不会相等。例如，当我通过编辑查询文本添加 FILTER 时，我会在相等性检查后得到所需的结果。但是当我以编程方式添加 FILTER 时，两个 FILTER 的序列化是相同的，但结果却不一样。这是一个示例，两个查询及其后立即显示的结果。

PREFIX  rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  person: <http://www.myOntDomain/person#>
PREFIX  likedEvent: <http://www.myOntDomain/likedEventRule#>
PREFIX  event: <http://www.myOntDomain/event#>
PREFIX  owl:  <http://www.w3.org/2002/07/owl#>
PREFIX  xsd:  <http://www.w3.org/2001/XMLSchema#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  weather: <http://www.myOntDomain/weather#>
PREFIX  eventHasSuitableWeather: <http://www.myOntDomain/eventHasSuitableWeather#>
PREFIX  freeAtEvent: <http://www.myOntDomain/freeAtEventRule#>

SELECT DISTINCT  ?Event ?Person ?Time
WHERE
  { ?Person   rdf:type              person:Person .
    ?Event    rdf:type              event:Event .
    ?WeatherEvent
              rdf:type              weather:WeatherEvent .
    ?WeatherType  rdf:type          weather:WeatherEventType .
    ?Person   likedEvent:likedEvents  ?Event ;
              freeAtEvent:freeAtEvent  ?Event .
    ?Event    eventHasSuitableWeather:eventHasSuitableWeather  true ;
              event:eventHasDate    ?Time .
    ?Person   person:hasName        ?PersonName ;
              person:hasAge         ?PersonAge .
    ?Event    event:hasEventType    ?EventType .
    FILTER ( ?Time = "2010-01-19T16:00:00Z"^^xsd:dateTime )
  }

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| Event                                                                   | Person                                            | Time                                                                |
=====================================================================================================================================================================================================
| <http://www.myOntDomain/event#SerlockHolmesMovie>          | <http://www.myOntDomain/person#Ayse> | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SerlockHolmesMovie>          | <http://www.myOntDomain/person#Ali>  | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SyntheticPitchFootballMatch> | <http://www.myOntDomain/person#Veli> | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
| <http://www.myOntDomain/event#SyntheticPitchFootballMatch> | <http://www.myOntDomain/person#Ali>  | "2010-01-19T16:00:00Z"^^<http://www.w3.org/2001/XMLSchema#dateTime> |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

PREFIX  rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  person: <http://www.myOntDomain/person#>
PREFIX  likedEvent: <http://www.myOntDomain/likedEventRule#>
PREFIX  event: <http://www.myOntDomain/event#>
PREFIX  owl:  <http://www.w3.org/2002/07/owl#>
PREFIX  xsd:  <http://www.w3.org/2001/XMLSchema#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  weather: <http://www.myOntDomain/weather#>
PREFIX  eventHasSuitableWeather: <http://www.myOntDomain/eventHasSuitableWeather#>
PREFIX  freeAtEvent: <http://www.myOntDomain/freeAtEventRule#>

SELECT DISTINCT  ?Event ?Person ?Time
WHERE
  { ?Person   rdf:type              person:Person .
    ?Event    rdf:type              event:Event .
    ?WeatherEvent
              rdf:type              weather:WeatherEvent .
    ?WeatherType  rdf:type          weather:WeatherEventType .
    ?Person   likedEvent:likedEvents  ?Event ;
              freeAtEvent:freeAtEvent  ?Event .
    ?Event    eventHasSuitableWeather:eventHasSuitableWeather  true ;
              event:eventHasDate    ?Time .
    ?Person   person:hasName        ?PersonName ;
              person:hasAge         ?PersonAge .
    ?Event    event:hasEventType    ?EventType .
    FILTER ( ?Time = "2010-01-19T16:00:00Z"^^xsd:dateTime )
    FILTER ( ?Time = "2010-01-19T16:00:00Z"^^xsd:dateTime )
  }

-------------------------
| Event | Person | Time |
=========================
-------------------------

更新

我在 jena-dev 中问了同样的问题，并了解到查询或代码没有任何问题。这是 Jena 2.6.0 中的一个问题，但它已在 Jena 2.6.2 中修复。

4

1 回答 1

0

您的查询没有明显错误，这可能是您使用的 SPARQL 引擎如何实现 = 运算符的问题。您使用的是哪个 SPARQL 引擎？

= 运算符应该执行值相等，因此当针对您的本体评估查询时，您的过滤器应该仍然返回大多数相同的结果。

即使 = 运算符仅在您使用的 SPARQL 引擎中执行 RDF 术语相等，您仍然应该得到结果，因为 Literals 仍然会完全匹配。

如果您发布您正在使用的 SPARQL 引擎和实际本体的副本，我可能会给您一个比“它应该可以工作”更好的答案

更新

I suspect but can't say for certain that this may be some strange issue in xsd:dateTime serialization/deserialization. I would send an email to the Jena developer mailing list detailing your problem and see if the developers and the community can give you an answer on this one:

http://tech.groups.yahoo.com/group/jena-dev/

于 2010-01-21T11:35:22.217 回答