The Study Of Using DTD To Optimize XML Query Based Path

XML is suitable for data representation, and it is being used widely in the area of DataBase and of exchanging data over the Web. There are some investigation on storage, and many storage methods for XML have been achieved. But it is inevitable to query on XML data after the application of XML becomes true. So it is essential to find an effective XML query language. Many people propose many kinds of XML query language, but their efficiency on time and space is not perfect yet. And it is crucial to have more studies on optimizing XML query languages existing now and proposing more tactics on XML query.With the growing popularity of XML, there are many criterions to restrict the structure of XML document. For every XML document, there is a DTD corresponding it to restrict its structure. On the base of this, for applying the DTD to XML query efficiently, a method for using the DTD to improve XML query is imposed in this article.A method for scanning DTD tree fleetly and a method for saving the scanning results are put forward, and the scanning results are named true paths. The background of this article is making software. And then, it provides the basic idea and algorithm of scanning DTD tree. And on the basis of the results of scanning DTD tree, namely, true paths, it produces the base idea and algorithm of scanning XML document tree. There are illustrations at the end of this article and it explains detailedly the theory that the methods provided in this article improve XML query based path.The significance for the ideas and algorithms proposed in this article means practicality. Though there are many studies on XML query, many of them are basis on theoretics. And many of them are only one part of one method of the XML query, and it is not implemented at present. In this article, not only the basic ideas are provided, but also the algorithms are produced. And they are implemented with the presenttechnologies. So it is enforceable.