[semihsalihoglu]

That's correct though OWL also provides ways to constraint what can be encoded (e.g., the cardinality constraint example I gave). But yes, SHACL is primarily for constraints. I general, there are several other standards than RDFS and OWL I didn't mention in the post. I wanted to give a few example standards to explain to show how RDF + standards forms something more than a regular data model that developers think of.

[compressedgas]

I mentioned SHACL specifically because it resolves your issue of lack of integrity as it serves the same role as schema definitions in RDF databases that support it. If any attempt at an insert fails the SHACL constraints, the attempted insert will be rejected.

OWL however is only used when doing selects. It expands queries to allow them to access things they didn't know to ask for. When used on top of an relational database, OWL expresses the kind of statements that exists in a T-box for ontology based access.