Manipulations like this (backed by the proper relational theory) 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。

youdao

The relational standardization theory is the relational database 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。

youdao

In this paper, it researches and realizes the mapping theory between the object and relational database, and manages the persistent objects.

论文对数据对象与关系数据库之间映射理论和持久化对象管理技术进行了研究和实现。

youdao