We address the problem of semantic querying of relational databases (RDB) modulo knowledge bases using very expressive knowledge representation formalisms, such as full first-order logic or its various fragments. We propose to use a first-order logic (FOL) reasoner for computing schematic answers to deductive queries, with the subsequent instantiation of these schematic answers using a conventional relational DBMS. In this research note, we outline the main idea of this technique -- using abstractions of databases and constrained clauses for deriving schematic answers. The proposed method can be directly used with regular RDB, including legacy databases. Moreover, we propose it as a potential basis for an efficient Web-scale semantic search technology.
The work presented here was originally inspired by the XSTONE project @cite_2 . In XSTONE, a resolution-based theorem prover (a reimplementation of Gandalf, which is, in particular, optimised for taxonomic reasoning) is integrated with an RDBMS by loading rows from a database as ground facts into the reasoner and using them to answer queries with resolution. The system is highly scalable in terms of expressiveness: it accepts full FOL with some useful extensions, and also has parsers for RDF, RDFS and OWL. We believe that our approach has better data scalability and can cope with very large databases which are beyond the reach of XSTONE, mostly because our approach obtains answers in bulk, and also due to the way we use highly-optimised RDBMS.
@cite_2
2096144498
Summary: We describe multiple methods for accessing and querying the complex and integrated cellular data in the BioCyc family of databases: access through multiple file formats, access through Application Program Interfaces (APIs) for LISP, Perl and Java, and SQL access through the BioWarehouse relational database. Availability: The Pathway Tools software and 20 BioCyc DBs in Tiers 1 and 2 are freely available to academic users; fees apply to some types of commercial use. For download instructions see http: BioCyc.org download.shtml Supplementary information: For more details on programmatic access to BioCyc DBs, see http: bioinformatics.ai.sri.com ptools ptools-resources.html Contact: [email protected]