Semantic Query for Integrated Heterogeneous Database Systems
Ping Liang, Yunsheng Liu, Shuming Liang, Heping Chen · 2008
To enable accessing deep web information at semantic level, this paper develops a semantic query rewriting mechanism on heterogeneous database enabled web information system with complex ontology mapping technology. It discusses the procedure of converting database schema and instances to ontologies at first, and then the patterns of complex ontology mappings, and the ontology-based query planning in Mediator-Wrapper based environment with GAV style querying request. The relational algebra rewriting is discussed in detail.