粗关系数据库查询模型

Query Model of Rough Relational Databases

针对粗关系数据库中数据的特性,提出一种不确定性数据的存储方法。基于汉明距离的一种变式,计算元组间距离,构成距离矩阵,根据距离矩阵将相同或相近的元组归类,从而有效地对表中的元组进行索引。借助粗集中的上、下近似,通过计算用户查询的数据与粗关系数据库中数据的相似度,查询出用户所需的数据。结合以上方法构建粗关系数据库查询模型,设计相应的查询算法并应用于实例中。

According to data characteristics of the Rough Relational Databases（RRDB）, a method for storing uncertainty data is put forward. An approach to index uncertain data is proposed based on Hamming distance. A query method is presented by using the similarity degree calculated between the data entered by users and the data being queried in RRDB based on the concepts of upper and lower approximation of rough sets. The theory methods mentioned above are combined, and the query model of RRDB is constructed. And an algorithm for querying data in RRDB is described and illustrated by using an analysis example. The real world example shows that the proposed approach is useful and effective.