Optimization of object queries containing encapsulated methods
Zhaohui Xie · 1993
Optimizationof object queries containing encapsulated methods is still an open problem.In some previous studies of object query optimization, encapsulated methods are considered w black boxes and therefore, optimal query evaluation plans may be excluded from consideration.In the others, only methods coded in query languages are taken into consideration during optimization process and the application of methods is, therefore, restricted.In this paper, a systematic way of revealing and exploiting useful information from encapsulated methods is applied in object query optimization.Some new strategies of object query optimization are proposed according to the classifications and evaluations of selections and joins containing path expressions or methods.Object query graphs are used to represent object queries and to capture different kinds of selections and joins.They are also used to factorize common sub path expressions among not only path expressions in queries but also maximal common sub argument path expressions in methods and to generate query evaluation plans.