This paper investigates the Web data aggregation issues in multidimensional on-line analytical processing （MOLAP） and presents a rule-driven aggregation approach. The core of the approach is defining aggregate rules...This paper investigates the Web data aggregation issues in multidimensional on-line analytical processing （MOLAP） and presents a rule-driven aggregation approach. The core of the approach is defining aggregate rules. To define the rules for reading warehouse data and computing aggregates, a rule definition language - array aggregation language （AAL） is developed. This language treats an array as a function from indexes to values and provides syntax and semantics based on monads. External functions can be called in aggregation rules to specify array reading, writing, and aggregating. Based on the features of AAL, array operations are unified as function operations, which can be easily expressed and automatically evaluated. To implement the aggregation approach, a processor for computing aggregates over the base cube and for materializing them in the data warehouse is built, and the component structure and working principle of the aggregation processor are introduced.展开更多
提出利用Cube中的维层次聚集树(d im ens ion h ierarchy aggregate tree,简称DHA_T ree)来对聚集Cube进行增量更新维护,在维层次聚集Cube中进行数据插入和删除等数据更新时,充分利用维层次聚集树中的维层次前缀,由下向上用更新前后的...提出利用Cube中的维层次聚集树(d im ens ion h ierarchy aggregate tree,简称DHA_T ree)来对聚集Cube进行增量更新维护,在维层次聚集Cube中进行数据插入和删除等数据更新时,充分利用维层次聚集树中的维层次前缀,由下向上用更新前后的差值对受到更新结点影响的所有祖先结点进行增量更新.在插入新维数据时,在不需要重新构建聚集Cube就可以对聚集Cube进行增量更新,从而减少了Cube的更新时间.对基于维层次聚集树的聚集Cube与传统Cube进行了算法性能分析和比较,结果表明本文所提出的聚集Cube的增量更新算法性能最佳.展开更多
基金The National Natural Science Foundationof China (No60573165)
文摘This paper investigates the Web data aggregation issues in multidimensional on-line analytical processing （MOLAP） and presents a rule-driven aggregation approach. The core of the approach is defining aggregate rules. To define the rules for reading warehouse data and computing aggregates, a rule definition language - array aggregation language （AAL） is developed. This language treats an array as a function from indexes to values and provides syntax and semantics based on monads. External functions can be called in aggregation rules to specify array reading, writing, and aggregating. Based on the features of AAL, array operations are unified as function operations, which can be easily expressed and automatically evaluated. To implement the aggregation approach, a processor for computing aggregates over the base cube and for materializing them in the data warehouse is built, and the component structure and working principle of the aggregation processor are introduced.
文摘提出利用Cube中的维层次聚集树(d im ens ion h ierarchy aggregate tree,简称DHA_T ree)来对聚集Cube进行增量更新维护,在维层次聚集Cube中进行数据插入和删除等数据更新时,充分利用维层次聚集树中的维层次前缀,由下向上用更新前后的差值对受到更新结点影响的所有祖先结点进行增量更新.在插入新维数据时,在不需要重新构建聚集Cube就可以对聚集Cube进行增量更新,从而减少了Cube的更新时间.对基于维层次聚集树的聚集Cube与传统Cube进行了算法性能分析和比较,结果表明本文所提出的聚集Cube的增量更新算法性能最佳.
