رئوس مطالب
- چکیده
- مقدمه
- ساختار XML و مدل دیتا
- با استفاده از دستاورد مبتنی بر نمودار
- ذخیره XML از یک طرح
- تکنیک های بهینه سازی پرس و جو
- پیمایش مسیر
- DataGuide (راهنمای دیتا)
- طرح شماره گذاری
- طرح پیشوند فشرده
- طرح لیبل گذاری پیشوند بر مبنای گروه (GPR)
Abstract
Over the past few years, XML (eXtensible Mark-up Language) has emerged as the standard for information representation and data exchange over the Internet. This paper provides a kick-start for new researches venturing in XML databases field. We survey the storage representation for XML document, review the XML query processing and optimization techniques with respect to the particular storage instance. Various optimization technologies have been developed to solve the query retrieval and updating problems. Towards the later year, most researchers proposed hybrid optimization techniques. Hybrid system opens the possibility of covering each technology’s weakness by its strengths. This paper reviews the advantages and limitations of optimization techniques.
Keywords: indexing - labeling scheme - query optimization - XML storageConclusions
The optimization of queries on small documents seems not very useful. But, as the usage of XML shifts towards the data-oriented paradigm, more efforts need to be done to allow the efficient retrieval and processing of query. This survey shown, there are three methods to store XML data, i.e via RDBMS, OODBMS and native database. The type of storage will determine the possible indexing mechanism. Various indexing technologies have been developed to solve the query retrieval and updating problems. A problem with path traversal methods is that traversing is only possible in the constrained set of path. However, for the structure summary indexing, most of it has the problem of large index size growth in the worst case and not supporting partial queries path matching. Labeling scheme allow quick determination of the relationships among the element nodes and reduce the index size, but fails to support dynamic XML data. Towards the later year, most researchers proposed hybrid-indexing techniques. Hybrid system opens the possibility of covering each technology’s weaknesses by its strengths.