【摘要】 一阶查询的SQL可表达性使得基于数据库修复的一阶查询重写方法在解决不一致数据库上的一致性查询问题上更具实际应用价值,但现有方法生成的一致性查询重写的执行效率不够理想.本文重点考虑在数据集成环境下如何有效地提高一致性查询的执行效率,同样针对合取查询类Cforest提出了基于OR-database集成模式的一致性查询重写算法ConsRewrite_OR.基于线性工作度量的查询代价分析以及Oracle 10g上的TPC-H模拟实验都充分地说明本文算法产生的一致性查询与Fuxman的查询重写相比在集成数据库上具有更好的执行效率.更多还原

【Abstract】 The expressiveness of first-order queries makes first-order query rewriting based on database repair has more practical value on solving CQA problem over inconsistent database compared with other methods. However,the execution efficiency of consistent query rewriting generated from the existing methods might be unsatisfactory. How to effectively promote the performance of consistent query in the data integration environment is studied principally in this paper. Facing the same conjunctive query class Cforest,the consistent query rewriting algorithm ConsRewrite_OR based on OR-database integration schema is presented. Both query cost analysis based on the linear work metric and TPC-H simulated experiments on Oracle 10 g adequately indicate that the consistent query rewriting produced by ConsRewrite_OR can obtain more optimized execution efficiency on integration databases,compared with Fuxman’s consistent query rewriting.更多还原