On Data Storage In SNAX

As a development of current Web, Semantic Web aims to enrich the Web data with semantic format and make them machine-readable. Thus it will be convenient for human to operate. The author researches on data storage approaches and technologies in the Semantic NAtive XML Database System (SNAX).Firstly, the author introduces Tim Berners-Lee's architecture of Semantic Web and SNAX and proposes the research direction and content in the thesis.Secondly, the author analyzes the current research on XML storage problem. Because of the general representation ability of XML format, its property of semistructure, its schema or data/document property and requirement of the different XML's application, the storage problem is becoming more complicated. There are three alternative schemas for storing XML data nowadays: one is to store XML documents as ASCII files in the operating file system; another is to use a commercial database management system to store; the third is to develop a special storage format and supporting software to store XML data.Finally, the author proposes a structural index called DOBI. By extracting DTD and storing OB structure, DOBI can well resolve the most basic connection question between the ancestor and offspring on structural query. It can efficiently realize all kinds of query. After analyzing the efficiency of query, the author proves that DOBI can quickly establish the relations among elements, reduce the route visiting times, save I/O resources, and realize the joins of XML documents effectively as well improve the efficiency of query.