计算机科学论坛--[求助]用sparql查询数据库中的本体，不知道错在哪里

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

以下是存储在数据库中的本体：
<?xml version="1.0"?>
<rdf:RDF
    xmlns="http://www.owl-ontologies.com/Ontology1215496170.owl#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
  xml:base="http://www.owl-ontologies.com/Ontology1215496170.owl">
  <owl:Ontology rdf:about=""/>
  <owl:Class rdf:ID="Company"/>
  <owl:Class rdf:ID="Trade"/>
  <owl:Class rdf:ID="People"/>
  <owl:ObjectProperty rdf:ID="belongTo">
    <rdfs:range rdf:resource="#Trade"/>
    <rdfs:domain>
      <owl:Class>
        <owl:unionOf rdf:parseType="Collection">
          <owl:Class rdf:about="#Company"/>
          <owl:Class rdf:about="#People"/>
        </owl:unionOf>
      </owl:Class>
    </rdfs:domain>
  </owl:ObjectProperty>
  <owl:ObjectProperty rdf:ID="workIn">
    <rdfs:range rdf:resource="#Company"/>
    <rdfs:domain rdf:resource="#People"/>
  </owl:ObjectProperty>
  <Company rdf:ID="CCB">
    <belongTo>
      <Trade rdf:ID="finace"/>
    </belongTo>
  </Company>
  <People rdf:ID="Tom">
    <workIn rdf:resource="#CCB"/>
  </People>
</rdf:RDF>

以下是程序文件：
import java.util.*;

import com.hp.hpl.jena.reasoner.*;

import com.hp.hpl.jena.query.*;

import com.hp.hpl.jena.reasoner.rulesys.*;

import com.hp.hpl.jena.ontology.*;

import com.hp.hpl.jena.db.*;

import com.hp.hpl.jena.rdf.model.*;

import com.hp.hpl.jena.util.*;

public class test{

public static void main(String args[]){
String strURL="jdbc:mysql://localhost/test";
  String strUser="root";
  String strPW="";
  String strDB="MySQL";
  String driver="com.mysql.jdbc.Driver";
  try{
  Class.forName(driver);
  }catch(ClassNotFoundException e){};

  // 创建一个数据库连接
  IDBConnection conn = new DBConnection (strURL, strUser, strPW, strDB );
  // 使用数据库连接参数创建一个模型制造器
  ModelMaker maker = ModelFactory.createModelRDBMaker(conn);
     // 创建一个默认模型，命名为test
     Model base = maker.createModel("test");
  OntModelSpec spec = new OntModelSpec(OntModelSpec.OWL_MEM);
  spec.setImportModelMaker(maker);
  OntModel newmodel = ModelFactory.createOntologyModel(spec,base);

  String rules="[rule:(?x http://www.test.com/medical#workIn ?y)(?y http://www.test.com/medical#belongTo ?z)->(?x http://www.test.com/medical#belongTo ?z)]";
  Reasoner reasoner=new GenericRuleReasoner(Rule.parseRules(rules));
  InfModel inf = ModelFactory.createInfModel(reasoner, newmodel);
//查询Tom属于哪个行业
  String queryString="PREFIX med:<http://www.test.com/medical#> "+
         "select ?person ?trade "+
         "where {?person med:belongTo ?trade}";

  Query query = QueryFactory.create(queryString);

     QueryExecution qe = QueryExecutionFactory.create(query, inf);
     ResultSet results = qe.execSelect();
     /*打印结果*/
     ResultSetFormatter.out(System.out, results, query);
     qe.close();

}
}

查询的结果显示为：
------------------
| person | trade |
==================
----------

不知道是sparql语句写的不对，所以出来的结果为空？还是程序中创建模型时创建的时空模型？不过后一种可能我想不会，因为在创建这个模型后，我可以将它的类和属性都读出来……不过不大确信
跪求高人解答！

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

Jena中的SPARQL不能检索推理之后的本体库中推理出来的内容，只能检索推理之前的原始本体库

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

谢谢jpz6311whu!!!
不过还是不明白,为什么只能检索推理之前的原始本体?如果是这样,那么需要查询推理之后的本体,该如何解决呢?

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

这个是因为Jena推理和存储机制的特点，它将原始本体和推理的新本体分开了，后者放在另外的posit里面，所以无法用SPARQL查询到

Extended list statements
The default API supports accessing all entailed information at the level of individual triples. This is surprisingly flexible but there are queries which cannot be easily supported this way. The first such is when the query needs to make reference to an expression which is not already present in the data. For example, in description logic systems it is often possible to ask if there are any instances of some class expression. Whereas using the triple-based approach we can only ask if there are any instances of some class already defined (though it could be defined by a bNode rather than be explicitly named).

To overcome this limitation the InfModel API supports a notion of "posit", that is a set of assertions which can be used to temporarily declare new information such as the definition of some class expression. These temporary assertions can then be referenced by the other arguments to the listStatements command. With the current reasoners this is an expensive operation, involving the temporary creation of an entire new model with the additional posits added and all inference has to start again from scratch. Thus it is worth considering preloading your data with expressions you might need to query over. However, for some external reasoners, especially description logic reasoners, we anticipate restricted uses of this form of listStatement will be important.

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

十分感谢!
看来这种查询只能使用InfModel类中的listStatements()方法了?
仔细看了远觉得没有使用sparql查询来得方便,比较沮丧的说……

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

可以推理查询的，我拿你了做了下实验。存数据库麻烦我就没做数据库的实验你可以做一下看，下面是我的程序，我把你的owl文件存名为1.owl，放在D盘根目录下，

1.owl文件如下：
<?xml version="1.0"?>
<rdf:RDF
    xmlns="http://www.owl-ontologies.com/Ontology1215496170.owl#"
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
    xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
  xml:base="http://www.owl-ontologies.com/Ontology1215496170.owl">
  <owl:Ontology rdf:about=""/>
  <owl:Class rdf:ID="Company"/>
  <owl:Class rdf:ID="Trade"/>
  <owl:Class rdf:ID="People"/>
  <owl:ObjectProperty rdf:ID="belongTo">
    <rdfs:range rdf:resource="#Trade"/>
    <rdfs:domain>
      <owl:Class>
        <owl:unionOf rdf:parseType="Collection">
          <owl:Class rdf:about="#Company"/>
          <owl:Class rdf:about="#People"/>
        </owl:unionOf>
      </owl:Class>
    </rdfs:domain>
  </owl:ObjectProperty>
  <owl:ObjectProperty rdf:ID="workIn">
    <rdfs:range rdf:resource="#Company"/>
    <rdfs:domain rdf:resource="#People"/>
  </owl:ObjectProperty>
  <Company rdf:ID="CCB">
    <belongTo>
      <Trade rdf:ID="finace"/>
    </belongTo>
  </Company>
  <People rdf:ID="Tom">
    <workIn rdf:resource="#CCB"/>
  </People>
</rdf:RDF>

我在java中的代码如下：

package test;

import java.io.File;
import java.io.FileInputStream;

import com.hp.hpl.jena.reasoner.*;

import com.hp.hpl.jena.query.*;

import com.hp.hpl.jena.reasoner.rulesys.*;

import com.hp.hpl.jena.ontology.*;

import com.hp.hpl.jena.rdf.model.*;

public class Test{

public static void main(String args[]){

  try
  {
  OntModel m = ModelFactory.createOntologyModel();
File file = new File("d:\\1.owl");
FileInputStream in = new FileInputStream(file);
m.read(in,null);

String rules="[rule:(?y http://www.owl-ontologies.com/Ontology1215496170.owl#belongTo ?z)"+
   "(?x http://www.owl-ontologies.com/Ontology1215496170.owl#workIn ?y)->"+
   "(?x http://www.owl-ontologies.com/Ontology1215496170.owl#belongTo ?z)]";
Reasoner reasoner=new GenericRuleReasoner(Rule.parseRules(rules));
InfModel inf = ModelFactory.createInfModel(reasoner, m);

String queryString="PREFIX med:<http://www.owl-ontologies.com/Ontology1215496170.owl#> "+
    "select ?person ?trade "+
    "where {?person med:belongTo ?trade}";

Query query = QueryFactory.create(queryString);
QueryExecution qe = QueryExecutionFactory.create(query, inf);
    ResultSet results = qe.execSelect();
    ResultSetFormatter.out(System.out, results, query);

  }catch(Exception e){e.printStackTrace();}
}
}

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

你的错误在于，你写规则文件写错了。规则文件里面的http://www.test.com/medical#
应该改为xmlns里面的http://www.owl-ontologies.com/Ontology1215496170.owl#

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

确实是规则文件中的名字空间写错了.修改之后通过数据库查询也通过!谢谢jxlhljh!!也谢谢jpz6311whu!

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

我按照上面修改规则得不到结果，不知道为什么？但是不从数据库中获取可以。

姓名：(无权查看)
城市：(无权查看)
院校：(无权查看)

你的结果不太对吧，你输出的是belongTo对象属性的定义域和值域所对应的实例，而并非真正满足你所定义的规则吧，因为多出了ccb finance这个结果，这是我的看法，请指教


	W 3 C h i n a ( since 2003 ) 旗下站点苏ICP备05006046号《全国人大常委会关于维护互联网安全的决定》《计算机信息网络国际联网安全保护管理办法》	132.813ms