A Mapping Strategy from the XML Schema to the Relational Schema Based on Query Cost

As an international standard of data exchange over the Web,XML has been applied in many fields. How to transform the XML document to the relational database is an important research topic.The paper studies the method of mapping the XML schema to the relational schema.After analysing the structure and syntax of the XML schema,extracting the semantic information of elements,finding the real complex type elements,the XML schema is transformed to E_Schema.The expression of E_schema is simple but complete.E_Schema is processed based on query cost,and the best schema is obtained,and then converted to the relational schema which keeps the original hierarchical relation. Finally a simple and excellent mapping scheme is implemented.