Object-Oriented Queries: Equivalence and Optimization
نویسندگان
چکیده
We are interested in eeciently accessing data in an object-oriented database. We have developed a query algebra which fully supports object identity and abstract data types, and have identiied a variety of algebraic query transformations. The equivalence of two queries is complicated by the presence of object identity. In this paper we deene a hierarchy of notions of equivalence for queries, and present examples of equivalent query transformations for each level of the hierarchy.
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