Nested Query Processing Techniques in Object-Oriented Databases

Abstract

Nested queries can simplify queries on a database for users. However, nested queries also increase the complexity of query processing. In this paper, we propose query processing techniques for nested queries in object-oriented databases. Nested query expressions are first transformed into a query graph by using query graph tranformation algorithm. We adapt Access Support Relations (ASRs) technique to represent us then converted to an execution plan which consists of a set of operators that we defined tp manipulate ASRs in the query processing. The structure of Access Support Relations is the same as relations in RDB, thus many processing techniques in relational databases can be directly applied in our query processing.