摘要
XML数据查询代价估计问题是一种典型的多元素查询条件代价估计问题。XML数据中的值信息分布不仅与其他值信息分布相关,还与XML数据中的结构信息相关,而且当XML数据结构比较复杂时,会形成高维元素,导致存储量和错误率大幅上升,因此本文提出用离散余弦变换(DCT)方法压缩多维直方图的代价估计算法解决上述问题。实验结果证明,提出的方法能减少存储空间和错误率。
Result size estimation algorithm for XML query is a typical type of multiple attributes dependent problems.The value distribution of XML involves not only the distribution of other values but also the structural information of XML which will lead to the multi--dimensional dependent element set if structural infomation itself is complex.In that case, storage and error rate,will rise a lot. To solve this problem, a new value prediction algorithm which using Discrete Cosine Transform to compress multi--dimensional histogram is introduced and such an algorithm proves to be efficient in reducing storage and error rate.
出处
《微计算机信息》
2009年第27期204-205,203,共3页
Control & Automation
关键词
XML
代价估计
离散余弦变换
XML
result size est imation
Discrete Cosine Transform
