Question

有没有办法以动态方式生成SPARQL查询？我试图做的是这样的事情：如果我有一个DBpedia资源r1和另一个DBpedia资源r2，这个查询

SELECT * WHERE { <r1> ?pre <r2> }

将返回2个资源之间的谓词和这个查询

SELECT * WHERE { <r1> ?pre1 ?obj1 . ?obj1 ?pre2 <r2> }

将返回这两个资源之间的所有谓词和对象（分两步）等等我试图以这样的方式构建这个查询：它会自动增加两个资源之间的对象和谓词数量（例如，分4步）？

Answer 1

我弄清楚如何解决这个问题.. 这是我的解决方案：

private String completeQuery(String coreQuery){
String completeQuery = "";
completeQuery += "SELECT * WHERE {"+ "\n";
completeQuery += coreQuery + "\n";
completeQuery =completeQuery + "}" + "\n" +"limit 5" ;
return completeQuery;}
public String link(String object1, String object2, int distance){
if(distance == 1){
    String Quer = "<http://dbpedia.org/resource/"+object1+">" + " ?pre1 " +"<http://dbpedia.org/resource/"+object2+">";
    return completeQuery(Quer);
} 
else {
    String query = "<http://dbpedia.org/resource/"+object1+">" + " ?pre1 ?obj1 " + ".\n";
    for(int i = 1; i < distance-1; i++){
        query += "?obj" + i + " ?pre" + (i+1) + " ?obj" + (i+1) + ".\n" ;

    }
    query  += "?obj" + (distance-1) + " ?pre" + distance + " " + "<http://dbpedia.org/resource/"+object2+">";
    return completeQuery(query);
}}

生成增量SPARQL查询

1 个答案: