| 摘要: |
| 数据立方体中有很多冗余信息,去除这些冗余信息不但可以节约存储空间,还可以加快计算速度.数据立方体中的元组可以划分为封闭元组和非封闭元组.对任何一个非封闭元组,一定存在一个封闭元组,它们都是从基本表的同一组元组中经过聚集运算得到的,因而具有相同的聚集函数值.去掉数据立方体中所有的非封闭元组就产生了一个封闭数据立方体.提出了封闭数据立方体的生成算法、查询算法和增量维护算法,并使用合成数据和实际数据做了一些实验.实验结果表明,封闭数据立方体技术是有效的. |
| 关键词: 数据仓库 联机分析处理 数据立方体 增量维护 压缩 |
| DOI： |
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| 基金项目:Supported by the National Natural Science Foundation of China under Grant No.60273017 (国家自然科学基金); the National High-Tech Research and Development Plan of China under Grant No.2002AA4Z3420 (国家高技术研究发展计划(863)); the National Grand Fundamental Research 973 Program of China under Grant No.2001CCA03003 (国家重点基础研究发展规划(973)) |
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| Research on Closed Data Cube Technology |
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LI Sheng-En,WANG Shan
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| Abstract: |
| There is a lot of redundant information in a data cube. Removing redundancy from a data cube can not only reduce the storage space but also accelerate the computation. Tuples of a data cube can be divided into closed-tuples and non-closed tuples. For any non-closed tuple, there exists a closed-tuple, and both are aggregated from the same set of tuples in a base table and have the same aggregated value. By removing all non-closed tuples, a data cube can be translated to a closed data cube. The algorithm of computing a closed data cube is given, answering a query and maintaining the closed data cube incrementally. The results of experiments are also presented by using both the synthetic and real-world data sets. The experimental results show that the closed data cube technique is effective. |
| Key words: data warehouse on-line analytical processing data cube incrementally maintenance compression |
