Manipulations like this (backed by the proper relationaltheory) are at the heart of database query optimizers. The resulting tree is shown in Figure 2.
此类操作(由恰当的关系理论作为支持)是数据库查询优化器的核心所在。
2
The relational standardization theory is the relationaldatabase development and the design important part.
关系规范化理论是关系数据库开发与设计的重要部分。
3
In this paper, it researches and realizes the mapping theory between the object and relationaldatabase, and manages the persistent objects.