摘要
当前关系数据库模糊查询的研究中,涉及到分组查询having子句中的模糊条件或相对语言量词的较少。在模糊理论的基础上对having子句进行了模糊扩展,并利用模糊集合隶属函数的α截集将模糊的having子句转化为标准的SQL语句,因此可以利用RDBMS对记录进行筛选,保证了查询的效率。利用模糊集合基数的非模糊表示法来计算带量词的having语句,计算简单,结果简洁。
There are few researches on fuzzy queries of relational databases involving the fuzzy conditions or relative linguistic quantifiers in ＂having＂ clause. Methods based on fuzzy set theory to these queries were presented here. The fuzzy conditions in ＂having＂ clause were translated to general SQL queries on the basis of-cut of membership function. Therefore, the tuples can be filtered by the RDBMS, which improves the efficiency of fuzzy queries. Nonfuzzy cardinality of fuzzy set was used to evaluate the quantified ＂having＂ clause, so the computation and the result became simple.
出处
《计算机应用》
CSCD
北大核心
2008年第5期1177-1179,1193,共4页
journal of Computer Applications
基金
江苏省六大人才高峰高层次人才培养对象资助项目(06-A-07)
南京信息工程大学校科研基金(Y644)
关键词
模糊查询
模糊集合
基数
分组查询
fuzzy queries
fuzzy set
cardinality
grouping queries
