  In this paper, an overview of the state of the art on knowledge graph
generation is provided, with focus on the two prevalent mapping languages: the
W3C recommended R2RML and its generalisation RML. We look into details on their
differences and explain how knowledge graphs, in the form of RDF graphs, can be
generated with each one of the two mapping languages. Then we assess if the
vocabulary terms were properly applied to the data and no violations occurred
on their use, either using R2RML or RML to generate the desired knowledge
graph.
