For this recipe, you need to have installed the RDF extension. If you didn't, have a look at the previous recipe. If you did, you might wonder what the terms RDF and SPARQL mean, as they are used throughout this extension. This will become clear right now.
The Resource Description Framework (RDF) is a model for data that can be interpreted by machines. While humans can read HTML on the Web, machines do not understand natural language and must therefore be given information in another form. Disambiguation is an important aspect; does Washington refer to the city or the person? And which person? To express this, information in RDF is referred to by URIs or URLs, just like we do with reconciliation in OpenRefine. This is why RDF comes in handy for reconciliation.
The SPARQL Protocol and RDF Query Language (a recursive acronym for SPARQL) is a language for querying RDF datasources. Traditional relational databases use SQL as a query language; RDF databases...