Research On The Storage Of Native XML Document For Unstructured Information

Along with the incredibly booming development of the Internet/Intranet, the quantity of the data exchanged on the Web is greatly increasing everyday. And most information now presents as unstructured forms such as emails, graphics, Web pages, workflows etc. instead of traditional structured forms. How to find out a uniform method to express and access the unstructured information is the kernel of information construction in all organizations and also is a new aspect of research at present.As the brand-new criterion on data express and data exchange, XML has a unique description mechanism for unstructured information. But the traditional database system has a deficient support for XML in the storage for the logical structure and intact information of the data, which greatly constraints the express, exchange and sharing of the unstructured information described by XML. Native XML database defines a logical model for XML document, with which to store the document as a basic logical unit, and is independent to the bottom physical storage model. Native XML database is just the one to provide the really efficient storage and retrieval ability for those unstructured information described by XML.Based on the viewpoint mentioned above, this thesis brings forward a uniform access strategy and realization scheme in a Native XML database as a tentative exploration to the mechanism research in access to the unstructured information. Mainly includes techniques and theories as follows:1. The combination of the subtree-based storage model with the document-based to ensure the efficiency and integrality of the data retrieval for all sorts of heterogeneous and context mixed data to the fullest extent;2. Dynamically branching and merging combined with the data mapping mechanism, supports the XML document efficiently and can improve the operation capability of the system to some extent;3. Referring to the characteristic of XQuery, It presents a new operation language for XML data, XQUL, which supports the query operation as well as the update operation on XML;4. The definition of three indexes of document, structure and value provides a multilevel access strategy for XML data from the site to the document and then to the element.During the program of"the Research of Web storage system based on XML"supported by the educate department of Hubei province, guided by the theories above, we also used some correlative technology of JAVA and XML and partly realized the DBNS(Dynamic Branching and Mapping Mechanism for Native XML Storage System) model.