A discussion came up on the W3C Semantic Web Healthcare and Life Sciences (HCLS) SIG mailing list around models in OWL, validation and XSD. I’m reproducing my response here, because it’s worthwhile for a larger audience and it involves some work from a TWCer (Jiao Tao), the Pellet ICV.
I feel I need to cut to the chase with this one: XML schema cannot validate semantic correctness.
It can validate that XML conforms to a particular schema, but that is syntactic. The OWL validator is nothing like a schema validator, first it produces a closure of all statements that can be inferred from the asserted information. This means that if a secondary ontology is used to describe some data, and that ontology integrates with the ontology that you’re attempting to validate against, you will get a valid result. An XML schema can only work with what’s in front of it.