Ontologies first is an idiocy! Whenever you deal with a real data environment, you discover that your use cases drive your data model. Not the opposite way. For example, the DBPedia ontology is plainly wrong (or outdated, I don't know). If you want the real data model, you really should infer it from the data itself (Guess what, you CAN do that. Because proper RDF auto-describes its data model. But it is a lot of work). The more i deal with data, the more i realize that the exposed data models are not matching the data. And that is a SHAME for whoever calls himself/herself a data engineer.