将RDF .ttl文件合并到一个文件数据库中-过滤并仅保留所需的数据/三元组

问题描述

我需要将1000多个.ttl文件合并到一个文件数据库中.如何合并它们并过滤源文件中的数据，并仅将所需数据保留在目标文件中?

I need to merge 1000+ .ttl files into one file database. How can I merge them with filtering the data in the source files and keep only the data needed in the target file?

谢谢

推荐答案

有很多选项，但是最简单的方法可能是使用Turtle解析器读取所有文件，然后让该解析器将其输出传递给处理程序，它先进行过滤，然后再将数据传递给Turtle编写器.

There's a number of options, but the simplest way is probably to have use a Turtle parser to read all the files, and let that parser pass its output to a handler which does the filtering before in turn passing the data to a Turtle writer.

类似的事情可能会起作用(使用RDF4J):

Something like this would probably work (using RDF4J):

  RDFWriter writer = org.eclipse.rdf4j.rio.Rio.createWriter(RDFFormat.TURTLE, outFile);

  writer.startRDF();
  for (File file : // loop over your 100+ input files) {
      Model data = Rio.parse(new FileInputStream(file), "", RDFFormat.TURTLE);
      for (Statement st: data) {
         if (// you want to keep this statement) {
              writer.handleStatement(st);
         }
      }
  }
  writer.endRDF();

或者，只需将所有文件加载到RDF存储库中，并使用SPARQL查询将数据取出并保存到输出文件中，或者，如果您愿意:使用SPARQL更新来删除您不需要在将整个存储库导出到文件之前使用.

Alternatively, just load all the files into an RDF Repository, and use SPARQL queries to get the data out and save to an output file, or if you prefer: use SPARQL updates to remove the data you don't want before exporting the entire repository to a file.

遵循这些原则(再次使用RDF4J):

Something along these lines (again using RDF4J):

 Repository rep = ... // your RDF repository, e.g. an in-memory store or native RDF database

 try (RepositoryConnection conn = rep.getConnection()) {

    // load all files into the database
    for (File file: // loop over input files) {
        conn.add(file, "", RDFFormat.TURTLE);
    }

    // do a sparql update to remove all instances of ex:Foo
    conn.prepareUpdate("DELETE WHERE { ?s a ex:Foo; ?p ?o }").execute();

    // export to file
    con.export(Rio.createWriter(RDFFormat.TURTLE, outFile));
 } finally {
    rep.shutDown();
 }

根据数据量/文件大小，您可能需要稍微扩展此基本设置(例如，通过使用事务而不是仅让连接自动提交).但是，希望您能理解一般的想法.

Depending on the amount of data / the size of your files, you may need to extend this basic setup a bit (for example by using transactions instead of just letting the connection auto-commit). But you get the general idea, hopefully.

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