Research Of Semi-structured Data Storage Technology On Xml

With the rapid development of Internet, the data on the net is increasing continuously. These data lacks unitive and fixed model. Moreover, these data is always irregular and mutative frequently. So, the model of semi-structured data emerges at the times require. Semi-structured data is a data type which is between structured data and unstructured data. It is very difficult to manage the semi-structured data effectively. And how to manage the semi-structured data effectively is becoming hot spot of research.The appearance of XML technology drives the development of semi-structured data. XML data is a self-descriptive semi-structured data, it is an efficient way to use XML document to manage semi-structured data. As relational database is relatively mature and stable in all areas, using relational database to store and operate XML data and changing semi-structured data into structured data is of great theoretical and practical value.The research of paper sets out from analyzing semi-structured data and XML related technology, and aims to design an algorithm to realize the mapping of semi-structured data to XML data and storage structure of semi-structured data to realize the mapping of XML data to relational database.The paper discusses definition and traits of semi-structured data further and analyzes mode description forms and mode extraction technology of semi-structured data, introduces conversion technology of XML and database detailedly.At present, the most representative mode description form of semi-structured data is OEM model which is a self-descriptive digraph with nesting and tag. The paper adopts representation of adjacency list to realize the storage of graph, and give the corresponding storage structure definition of each object. Through the traversal of OEM model chart, convert the corresponding chart structure of OEM model to XML document and generate XML data to realize the mapping process of semi-structured data to XML Document. Paper presents a conversion algorithm to achieve the generation of XML data based on the idea of depth-first traversal.The data we get is a no-mode XML data document which does not have the existence of attributes, only the existence of elements. On the base of XML document generated, paper adopts a model mapping method based on prefix-encoding through analyzing the mutual mapping methods of XML document and database technology to realize the mapping of XML data and database.Finally, the paper presents a simple semi-structural Electronic Medical Records data to realize the mapping of semi-structured data to relational database, and give some typical XML query examples. Indeed realize the data management model of "storage means by relational database, medium of exchange by XML technology" using XML technology and existing relational database technology.