关系型数据库中不确定性数据的Top-k查询研究

Top-k查询在传统的存储确定性数据的关系型数据库中得到了广泛的应用,但是对于存储不确定性数据的数据库,Top-k查询必须结合元组的分值和不确定性来处理.已有的Top-k查询没有很好地结合元组的分值和不确定性,因此,定义一种新的针对不确定性数据的Top-k查询语义,并且实现了查询算法,在新语义下,计算第i位排名时考虑了第i-1位元组,能够更好地权衡分值和不确定性.不同数据集上的实验显示,该算法是有效的.

STUDY ON Top-k QUERY OF UNCERTAINTY DATA IN RELATIONAL DATABASE

Top-k query has been widely applied in traditional relational databases storing the deterministic data,but for the databases storing uncertainty data.Top-k query have to process in conjunction with the score and uncertainty of tuples.Existing Top-k query does not combine them well,therefore a new semantics of Top-k query for uncertainty data is defined,and the query algorithm is implemented.In this new semantics,the tuple at rank i-1 is considered when computing the tuple at rank i,so it better balances the score and uncertainty of tuples.Experiments on different data sets demonstrate the efficiency of the algorithm.