Research And Implement Of The Data Exchange Model

With the rapid development of Internet and the information technology, the information which is stored in the information systems is increasing enormously. On one hand, the data sources are heterogeneous, distributive and dynamic. These characters seriously block the data exchange between each data source. On the other hand,new requirements need exchange data between each system to accomplish new functions. The contradiction of these two aspects demands urgently data exchange between heterogeneous data sources in spite of the heterogeneity of the data model, data extraction, data synthesis, and other issues. The traditional data exchange model can only use to exchange the information on the structure level, but is not able to solve the semantic heterogeneity. So it causes that mass of valuable information for user is not be used. In addition, most of the current research focuses on the data integration which only supports the data query.This thesis researches data exchange of the heterogeneous data sources and their semantic heterogeneous problem in depth. Firstly, it describes the main methods of data integration and the role of ontology in the data integration and discusses the advantages and disadvantages of three typical ontology-based methods. Then, the thesis presents a new method which is based on the frontal analysis. In order to decrease local ontologies which are built from the similar data sources, it changes the absolute one-to-one relationship between the local ontology and the data source and establishes a one-to-many relationship between the local shared ontology and the similar data sources. Secondly, it presents a new data exchange model. This model makes use of the local shared ontology to integrate each data source to provide a global virtual view for the data exchange and solve the semantic heterogeneity. It uses the message as a carrier to transport the information between the data sources and ensures that the communication is independent of the platform. The uniform format of the information which the model transports between each data source is defined by the XML Schema. The processes of the data exchange in the mode of the Response-Request and Publish -Subscribe which the model supports is described in detail. Lastly, it studies the construction method of the ontology and its mapping and implements a prototype system.The research of this thesis deepens the application of the data integration and preliminarily solves the semantic heterogeneous problem of the data exchange and provides a new instructional framework for the data exchange system.