Research on Learning OWL Ontology from Relational Database

Ontology learning is the pivotal technology to construct knowledge base efficiently, and the data of existing knowledge systems are mostly organized in relational mode. In order to reuse and share knowledge in existing knowledge systems, it is necessary to construct ontology for existing knowledge systems. After comparing and analyzing the formal definitions of relational data schema and ontology, this paper proposes a method of extracting knowledge ontology from relational data model. This method builds OWL ontology knowledge base architecture based on metadata of relational data schema, maps different data elements into components of OWL ontology, and implements with prototype tool based on Java platform. As a case study, this method is applied to transform the database of online examination system into OWL ontology model. The method proposed in this paper can be applied to the practice of transferring the widely existing relational-based knowledge base system to the knowledge base system based on OWL ontology framework.