An efficient method for XML queries optimization based DTD abstraction and classification

With widespread application of XML documents, efficient access to XML data has become a key problem that needs to be solved. In this paper, it is proposed that a new method which realized optimization as querying, using XML documents' DTD. The goal of the method is to reduce the searching space when XML documents are queried. The method, which gains the classified information from DTD statically and uses them dynamically in query, does not need the extra index storage space. As there are XML documents without DTD, a method is brought to extract the DTD information from them through items appearance statistically.