Ontology learning is a process, which extracts semantic information from the existing data model and generates ontology using a set of predefined mapping rules. Relational database is the main model of data access and management, and extracting ontology from relational database is one of the research hotspots in ontology engineering field. A common method adopted by the domestic and foreign scholars is that ontology is constructed by using mapping rules between E- R model and ontology elements. But this method is subjective and it goes against the application of ontology. To address this issue...
