Foundations of a new proposal for querying relational databases and XML documents

Today, a large amount of information has been stored in XML, which has become the most useful standard of data interchange in the web and e-business world. Nonetheless, a large quantity of information remains stored in Relational Databases. It is very important to be able to jointly manage these two data formats. One solution would be an integrated query model that would at the same time allow the query of a relational database and of XML data. Because of the growing number of applications that have to work in a web environment, the proposed system should use a query language based in XML and also return answers in the same XML format. After having made a detailed study, in this paper we make comparing different systems that link both, databases and XML. Besides, we propose a new system to overcome the limitations found in them.