Hi everyone,
During my diploma thesis internship at Merck I created an open-source tool for converting big RDF datasets to RDB (relational database), JSON and other formats.
Check out chapter 7 to see how I converted a subset of Wikidata to a relational database model and used SQL to get results. The thesis is here: http://davidprihoda.com/rdf2x/Distributed_Conversion_of_RDF_Data_to_the_Rela...
The code is available on github: https://github.com/Merck/rdf2x.
Looking forward to any comments, Cheers, David Příhoda
wikidata-tech@lists.wikimedia.org