Research On XML Storage And Query Based On Relational Database

The invention of XML (Extensible Markup Language) changes the situation of web totally. XML has many advantages compared with HTML: semi-structure, self-description, flexibility and extensibility etc. It makes the separation of structure, content and display, which is good for data exchanges, personalized display and data integration among computers. Therefore, XML has been paid attention to widely since it is issued, and became the standard of data representation, exchange, and integration on web. At present, there is huge amount of XML data on the internet. It is very urgent to store and retrieve these XML data efficiently.This paper focuses on storage and query based on relational database. If the content of XML document could be stored into relational database, there would be mature techniques of relational database to be utilized. Thus, storage and query of XML in relational database has become a hot topic. But it is necessary for the storage methods of present to design different mapping rule for different mode by establishing different relational table, so it is lack of generality. Furthermore, the methods always are about DTD that is not the XML mode of W3C recommendation and it has many disadvantage- es. Therefore, this paper designs a XML relational storage method of mode mapping, which is based on XML Schema that is XML mode of W3C recommendation. It designs a universal mapping rules and relational table for all XML documents and XML Schemas to achieve generality and maintenance, and it also can store and query XML data very convenient. Moreover, it's very efficient to validate XML data by this way. The primary tasks of the paper are as follows:Firstly, it analyses the present researches on XML storage technologies, summarize many advantages of XML storage methods based on relational database in XML enabled database. It is one of good choices for solveing XML storage; Secondly, we find disadvantages of XML storage methods based on relational database at present, Then design a better method for XML storage based on relational database--XML relational storage method of mode mapping. It analyses the thought of storage, the implementation of storage, and the return and validation of XML based on this mode mapping. At last, it studies the XQuery query processing based on relational database, gives the normalization of XML query sentence and the translation processing from XQuery sentence to SQL sentence, and the specific query processing.