Incremental Optimization Query in XPath with the Tree Automaton

For the processing of query in the mass data, the user may adjust their query inquire, or add some uncertain factors in their query, or specify their query inquire, on the basis of their query result they have gained dynamically. To meet their inquire, we need to adjust our query actuator to adapt these changes and optimize the query to slove the query with lot of descendant operator ldquo//rdquo and free element operator ldquo*rdquo effectively when the query set be changed. Refer to these problems, on the basis of tree automaton, we make use of the structure flexible of the automaton to adjust the query set dynamically, and for the constrain of the DTD to the XML document, we use DTD automaton to optimize the XPath automaton. The experiment proved that the algorithm can improve the effiency of query in dynamic XML data stream on the cost of finite space.