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In recent years, with the rapid development of the Internet and the information industry , the amount of data to show explosive growth , database technology has been widely applied . However, there are a variety of differences in the choice of a data processing system , data sources vary widely , the formation of a huge , heterogeneous database environment , how to become a major problem faced by people sharing these heterogeneous data . XML technology has been appeared in the heterogeneous data exchange shows a powerful force, and quickly became a platform-independent , vendor-independent data format standard , not flexible format of EDI, and other traditional data exchange technology has overcome costly interaction defects and poor. In this paper, XML technology to establish the model of data exchange , XML document as a carrier for data exchange , and the design exchange rules dictionary -based XML document format , with pre-defined conversion rules constrain the conversion process , good solve the problems of the structural conflict in the conversion process , semantic conflicts . Carried out in-depth research paper on the two - way conversion rules of the database schema and XML schema , proposed an improved mapping method based on the object tree . Object tree to determine the mapping between XML document and database schema in the data structure , to ensure the correctness of the the mode mapping process data structure , to retain the integrity of the semantic constraints of the relational schema , primary key , foreign key , data types , and default values condition. The paper has also established a database data and XML documents , database data types and XML Schema datatypes two mapping rules . Finally, the use of a database instance , a detailed explanation of the bi-directional mapping process between relational databases and XML Schema documents .
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