面向对象数据库中“联系-选择”复合操作的优化  

OPTIMIZATION OF "ASSOCIATE-SELECT" COMPOUND OPERATION IN OBJECT-ORIENTED; DATABASE SYSTEMS

作　　者：吴胜利[1] 王能斌[2] 

机构地区：[1]中国科学院软件研究所,北京100080 [2]东南大学计算机科学与工程系,南京210096

出　　处：《软件学报》1997年第12期907-913,共7页Journal of Software

摘　　要：在面向对象数据库中，“联系-选择”复合操作的功能类似于嵌套关系数据库中多个嵌套关系的连接，是查询优化时需要重点考虑的问题．本文首先证明满足一定条件限制的“联系-选择”复合操作可在多项式时间内得到最佳查询方案，然后给出了支持双向联系时“联系-选择”复合操作的一些优化算法．模拟实验表明，文中所提出的优化算法性能平稳，效果很好．Associate-Select' compound operation, which is similar in functionality tojoin operation of multi-nested relations in nested relational databases, is a key issue ofquery optimization in object-oriented database systems. This paper proves that the opti-mum solution for treelike 'Associate-Select' queries with some restrictions can be obtainedwith polynomial complexity, then presents some algorithrns to deal with the situationwhen birelationship exists in complex objects(for example by defining inverse attribute etal. ). A simulation experiment is performed to demonstrate the steadiness and effectivenes s of the algorithms proposed in the paper.

关 键 词：面向对象 数据库 查询优化 复合操作 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]