SoftFacts is an ontology mediated database system. An ontology layer may be used to define (in terms of a DLR-Lite like description logic, an extension of DL-Lite) the relevant abstract concepts and relations of the application domain, while a database may be used to access large volumes of data. The supported databases are, so far, MySQL, Postgres and RankSQL (for top-k retrieval). It supports also a significant set of OWL QL profile language expressions via the SoftFacts tab for OWL editor Protégé.
SoftFacts's most interesting features are:
- Extended DLR-Lite and, thus, DL-Lite: as logical language for schema/ontology specification.
- Conjunctive Queries: as query language
- Relational Database: data is stored into relational database
- Top-k Query Answering: Supports top-k retrieval (find top-k scored tuples satisfying query), e.g. "find cheap hotels close to the train station", where cheap and price are a function of the distance and price, respectively.
- A plugin for OWL editor Protégé is provided