Different RDB to RDF mapping languages

This document deals with the different techniques, mapping languages ,tools ,applications used for mapping Relational Databastes and Resource Description Framework.This document will serve as a guide for selecting a particular language for mapping .For the development of semantic web we need to map Relational Database to Resource Description Framework.Since most of the data on web is stored on RelationalDatabase and a conceptual gap is to be bridged between the Relational Database model and RDF to make this data available on web semantic.Many mapping languages and approaches have been found leading to the ongoing standardization of the World WideWeb Consortium(W3C) carried out in the RDB2RDF Working Group(WG).This paper would provide help and recommendations for selecting a mapping language.