Research On The XML Technologies For Data Querying & Sharing And Their Applications

With the emergence of a large number of XML data, how to store effectively, manage, share, and query these XML data has become an important topic worthy of study. At present, the technology of XML data management is a hot topic in the field of database. In this paper, we research on the key technologies of the XML data sharing and querying, including XML index, the incremental maintenance of continuous query evaluator over XML Data Stream based on the tree structure and a data exchanging model based on XML technique. The main contributions and innovations of this dissertation are as follows:1)In the development of the XML, how to query XML documents has been a hot topic. How to quickly and efficiently judge whether the two elements have a relationship of ancestor/descendant is very important. Now the existed prime number labeling needs a number of primes and many big primes, therefore, an improved prime number labeling scheme is proposed. It's no need to use new prime numbers for each node in this method. The numbers of prime and the large prime are reduced in the MBPrime scheme. Thus, the MBPrime scheme speeds up the querying.2)A XML query maintenance based on tree structure—TSQM is proposed. TSQM algorithm is an incremental maintenance of continuous query evaluator over XML data stream using the tree structure to express the Xpath query. TSQM algorithm uses tree structure to express the coalition of the relationships between the XML nodes such as"//","*"and uses the automata to express the conversion of state. TSQM algorithm without adding the initial states is aimed at the dynamic maintenance of tree structure, which avoids the cases of the annular structure operation in the absence of a DTD and reduces the time of maintenance and the number of the transitions of state. TSQM algorithm can efficiently maintain the evaluator of the continuous query over XML data stream at a low cost of extra transitions of paths, and reduces the time of maintenance and the number of the transitions of state.3)A data exchanging model based on XML technique is proposed. Using XML documents as the base of data communication carrier, the information communication platform under Internet/Intranet environment is established and the software component is developed, which provides an effective low-cost method and tool to integrate and share different format data between heterogeneous databases. In this article we realize the data exchanging based on the XML technique, which is during the classed environment departments in the database management system of Fatal Environmental Contaminator Accident Danger, and discuss the operation principles and application modes of XML information exchange among enterprises.