Mapping Between RDBMS And Ontology A Review

Abstract Today Semantic web is playing a key role in the intelligent retrieval of information. It is the new-generation Web that tries to represent information such that it can be used by machines not just for display purposes but for automation integration and reuse across applications. It allows the representation and exchange of information in a meaningful way. Ontologies form the backbone of the Semantic Web they allow machine understanding of information through the links between the information resources and the terms in the ontologies. Ontology describes basic concepts in a domain and defines relations among them. An ontology together with a set of individual instances of classes constitutes a knowledge base. An effort has been made by the Semantic Web community to apply its semantic techniques in open distributed and heterogeneous Web environments and for sharing the knowledge in the semantic web. For sharing the knowledge ontologies were introduced and have grown considerably in number. Building ontology for a specific domain may be start from scratch or by modifying or using an existing ontology. The term Semantic Web SW given by Tim Berners Lee is considered as vast concept within itself. Semantic Web SW is defined as collection of information linked in a way so that it can be easily processed by machines. It is information in machine form. It contains Semantic Web Documents SWDs that are written in RDF or OWL languages. They contain relevant information regarding users query. Crawlers play vital role in accessing information from SWDs.