Heterogeneous Data Source Data Exchange Engine Design And Implementation

There are many irregularities, such as multi-flat, variety database,variety circulating way and dispersion in great disorder; exist in manyinformation management system of college. It is one of the core topics of theestablishment of numeral turn campus to build unitive information flat.Heterogeneous database have very big of difference and autonomy because of thedifference of structure, data, DBMS, hardware and network protocol. To solvethe communicate problem among the heterogeneous databases, It is the first andfoundation problem to set up a heterogeneous database engine for data exchange.This paper form the engine by the use of XML data model, according to the ideaof catalogue service, and band the P2P together with distribute networkorganically.The XML is a kind data format which defines by open self-description way.It includes document format standard (Schema), document manifestation modedefinition (XSL), document query standard (XQuery), document analyze standard(SAX) and document Link standard (XLink). As a kind of meta-markup language,the XML can order markup aim at dissimilarity application environments andrequests, and descript and exchange data with unify, open, mode according todocument format. The XML Schema is a kind of standard XML document. It has verystrong of description ability, expand ability and processing maintenanceability, by using XML as a description means. The XQuery is the function languagewhich gathers to carry on a query to the XML data. It is simple vivid, be easyto comprehension and realization.The P2P(peer-to-peer) is also called an equal net, customer can direct linkto the other computers on the net, and carry on a file sharing and exchange. P2Pis make up of physical distribute nodes. All nodes are equal. Each node has thesame responsibility and ability, and cooperates with the common mission. Theequal node is direct connecting with each other, sharing information resources, need no centralize server. In the P2P mode, the equal node has a very highautonomy and willingness. They are the consumer (the client) of information,and are also the promoter (the server) of information, share homology of functionat performing calculation, provide and consume.The paper introduces the total design of the heterogeneous database enginefor data exchange, including the total system structure, the system functionmodules, the system total process and the development environment.The paper gives a model of the data exchange engine. The paper takes javaas the program language, uses the XML Schema to define data module, and developsa simple realization model for the data exchange engine. The model provides thefunction of template. Opposite at the other system demand the customer acquaintwith the query language, and input an importation detailed of query languagesentence to hand over the query, this system provides template-customizationservice for the customer. Customer just need to select the data want to queryon the friendly user interface, then can immediately hand over the query, andcustomize the query asatemplate for the direct use later. Then the paper givesthe design and realization of the query processor. The whole query processdefines as query regularization, query decomposes, and query rewrite and queryresult synthesize, and then gives the realization arithmetic. At last, it givesthe working theory and the main class of the model.The model uses the example databases of Access, SQL Server and oracle toapply the data exchange. The paper gives a material appliance of the mode andintroduces its characteristics.At last, a summary of the paper is going, and the further research is putforward.