Knowledge Graph Construction with (R2)RML

RPT can translate RML and R2RML to SPARQL that can be run either with the integrate (single-threaded) or the sansa query (multi-threaded) commands. Note, that the generated SPARQL queries can be also be executed against the SPARQL endpoint launched by rpt integrate --server. This can be used to test and inspect individual SPARQL queries and the corresponding (R2)RML mappings.

Basic Usage

Conversion of RML files to SPARQL

• Convert an RML file to a sequence of SPARQL queries using rmltk’s rml to sparql command:

    rpt rmltk rml to sparql mapping.rml.ttl > mapping.raw.rml.rq
  

• Group and/or reorder SPARQL queries using rmltk’s optimize workload command:

    rpt rmltk optimize workload mapping.raw.rml.rq --no-order > mapping.rml.rq
  

Executing the mapping process

• … using the single threaded Jena engine:

    rpt integrate mapping.rq
  

• Using RPT’s parallel Spark-based executor:

    rpt sansa query mapping.rq
  

Core Technology

The core technology, i.e. the API and SPARQL converters, are part of our (R2)RML-Toolkit.