A computer-implemented method, computer-implemented system, and a computer program product for answering a database-based query of a computerized database system. The method includes: generating a canonical individual ind' with respect to a role and a concept, for an existential restriction in an ontology used in the computerized database system; converting implicit data in original data into explicit data using the canonical individual ind' and the ontology; and retrieving an answer meeting all query conditions in a query from the original data and the converted explicit data. The computer-implemented system includes: a canonical individual generation unit; a data conversion engine; and a query unit.
展开▼
