2 · FIBO Reuse and the OWL 2 QL Profile

FIBO in two paragraphs

FIBO (Financial Industry Business Ontology, EDM Council) is the de-facto OWL ontology for financial concepts. It defines legal entities, parties, instruments, contracts, accounts, dates — all the vocabulary banks already use, formalised. Major regulators (FRB, ECB) actively endorse it.

The disciplined move: subclass FIBO, don't replace it. A :ReportableCounterparty is just a fibo:LegalPerson with an extra reporting predicate. Three lines of Turtle.

What OWL 2 QL allows (and doesn't)

QL is deliberately the smallest OWL 2 profile — every axiom in it must be rewritable into SQL on a relational schema. What QL allows:

• rdfs:subClassOf (between named classes only)
• rdfs:subPropertyOf, owl:inverseOf, rdfs:domain, rdfs:range
• owl:disjointWith (class disjointness)
• Existential restrictions on the right-hand side only (A subClassOf hasX some Y)

What QL forbids (and why):

• Functional / inverse-functional properties — they would require row-level uniqueness checks beyond what query rewriting can express.
• owl:equivalentClass between complex expressions — would push reasoning out of AC0.
• Universal restrictions (only) — same.
• Number restrictions (cardinality 2) — same.

The pay-off: SPARQL gets rewritten into a single SQL query that the DWH planner optimises. The ontology costs nothing at runtime beyond a constant factor.

The trade-off in one line

MedaCore (DL) reasons; NorthWind (EL) classifies; Atlas (QL) rewrites.