When we are translating SQL into relational algebra, we need a simple but flexible form to represent the data structure involved. As an interim result of the calculation, relational algebra tree combined with object-oriented model can gives us simple, intuitive notation allowing the query to be efficiently expressed and implemented at amazing ease.

Since we have already designed a flexible form of representing the Relational Algebra Tree (RAT) translated by the SQL parser, the application of this kind of object-oriented representation should be explored. In this paper, we will show you how to apply this technique to complicated scenarios. The application of Reverse Query Processing and Reverse Manipulate Processing related to this issue will be discussed.