Design And Realization For Query Groupware Of Universal Resources Management System

In order to exchange and share the resource, and the efficiency and the level of resource construction is lower, we put forward a concept about union resource database, which is to build a resource platform. On the platform, we can search and manage different standard type resource through resource type enrollment mechanism.Because of the huge data quantity of the union resource management platform, frequent real time operation and diversification of the data type, the traditional database manage model can't adapt to the request of the system. So we adopt a XML half-structured database model and it also brings new questions to our search operation.After investigating the existing algorithm, we find that the implementation is based on the idea that whole XML document must be loaded into memory. While XML document is too large or can't be loaded into memory, algorithm is of no effect.To solve this question, we present a different method of the union resource manage platform in this paper. According to the query expression, a query automaton is build, whose strict and states imply the query predicate. The XML stream is parsed into element tag and text events stream. Those events such as start element event, text event or end element event trigger states transition of query automaton. To reduce memory requirement, the document fragment should be put into output immediately as soon as it meets query expression.We present a method of building query automaton and an implementation of XML stream query system. This implementation could evaluate the XPath expression in one-pass scan of xml stream. Finally we make a comparative experiment to investigate the memory use of memory-based algorithm and the steam-based algorithm.XML stream querying problem is introduced to meet the querying requirement of some data-intensive application. These applications adapt to stream data model instead of persistent data model. Stream data model can be used in many fields such as financial service, network monitor, communication data management, manufacture, sensor network. Research in this paper contributes to the theory and practice of this kind of applications.