Tightly Coupled Under The Xml Data Stored

With the rapid development of the Internet and the Web, the XML , an extensible markup language, become the ideal public format that mean many kinds of data with its characteristics such as self-descriptiveness, separability of content and representation etc. Large amounts of data is stored, issued and exchanged with XML format.Processing XML data contains two kinds of techniques: XML-Enabled DBMS (XED) and Native XML DBMS (NXD). This paper discusses primarily of XED. XED is a quite good selection on condition that the application demands simple format or data content is more important than format, especially the XML access interface on the existing database is in demand .The combination of XML and database has become an inevitable trend. Realizing bidirectional transmission of data between XML document and database is among hotspot in the study of XML technique application. At present, relational database is the primary data-saving mode. The pattern of data management that relation data regarded as saving means and XML as the exchange carrier has become the trend. When data in XML and data in relation table are closely coupling, conversion of data between them is more efficient. Mapping relation between XML and database has been created. After receiving XML, database decomposes them into field and save them in common way. When retrieving XML, these fields will be concatenated into original shape to establish the data that every kind of application program can read. The client may use only a standard language XML to interactive proceed with different database. This lowers the complexity of data exchanging and unify the data interface. This paper has done the elementary study on this direction. It introduces the knowledge relate to XML and database system, probes into the parsing technique of XML document, analyses and expatiates the bidirectional mapping between XML data and relational database circumstanced close coupling, discusses two sorts of mapping mechanism based on table and object. It utilizes the characteristic of DTD and XML Schema to realize the interconvert between relation mode and XML mode, and instances to analyze the mapping procedure. This mapping modeling is in the data of XML document, so it is a good choice for data-centric document.Traditional relational database is two-dimensional. However, the complicated multidimensional-relation still exists in practical application. In multidimensional data model, data is organized and displayed in multidimensional logical method. The data crosses mutually each dimension, forms the stereoscopic data view. This paper also introduces the saving mode and the pattern of multidimensional data, elementally discusses the mapping between it and XML document.The research of the convert relation and procedure between traditional database and XML document can make the most of the accumulation of traditional database technique in the course of twenty to thirty years. This study has good advantage for safeness, availability and flexibility, etc. especially for the field of finance, insurance, weather, earthquake...etc.which is exigent of data safeness and exchange.