Research Of Storing Data Using Relational Database In ASCM System Based On XML

Because of the time difference and spatial differentiation, different agricultural database systems have different hardware devices, runtime environments, operating systems, data models and so on. That seriously impacts on the real-time transmission of information, influence coordination and stability of ASCM system,and makes it impossible to share informations between different application systems, and breaks the chain in agricultral productions′production-supply-marketing.The unbalance between demand and supply largely handicap the development of agricultural producation. Therefore, we have to gather different source ,format, characteristics and properties of heterogeneous data logically or physically together organically, that can provide comprehensive data sharing for members of the ASCM network system.XML has customizable , portability , expansibility etc advantages,and facilitately express all types of data , is often used as data storage and exchange intermediary. Meanwhile XML data stored content and applications separately, that can improve the efficiency of data exchange and inquires. At present XML has a wide range of applic- ations in many fields. Efficiency, stability,portability and expansibility of relational database technology in mass data processing is incomparable,this technology can process XML data and relational data in a system.XML and relational database techn- ology union can effectively solve the problem of the integration of heterogeneous data in ASCM system.This paper mainly discussed how to store XML data documen using relational database in ASCM system, on the basis of model mapping and Structure mapping methods combined with the characteristics of ASCM system data, realizing XML data effective storage in relational model, to lay a foundation for eatablishing a unified ASCM system information sharing platform.Firstly by analysising existing data,acco- rding to the model defined types of XML data, the original data in ASCM system divided into three types:no model data,simple model data and complex model data,for different types of XML data take different storage ways. In no mode data storage process, this paper mainly introduces the establishment of XML document tree and no model data storage model. In simple mode data storage process, considering of characteristics such as large amount of data and updates faster in ASCM system, we proposeed an inline schema mapping algorithm. Conversion process must take into account hierarchy and ordering of XML data, and keep the XML schema information as much as possible to facilitate document reconstruction. In complex mode data storage process,We can extract some key informations,such as choice elements, complex elements, many-valued elements and groups of elements,through converting complex mode equivalent model.Then, we can establis hing DOM tree according to equivalence information,combining mapping rules,XML complex model can be converted to relational model. Finally, loading the XML document, the XML document data would be added to database table,which would achieve conversion XML document data to relational database.