This is necessary to isolate the relational layer from the object layer, but this convenience comes at the cost of performance.

这对于将关系层与对象层分离是必需的，但这种便利是以牺牲性能为代价获得的。

youdao

The PDH interface is an abstraction of the details required to retrieve performance object and performance counter data from the Windows Registry.

PD H接口是从Windows Registry中检索性能对象和性能计数器所需的细节的抽象。

youdao

Based on the sample of corporate control replacing mergers and acquisitions of listed companies from 1993 to 2003 in China, the paper carries out empirical studies on performance of object companies.

以我国1993 ~ 2003年上市公司控制权转移并购为样本，研究了目标公司在并购前后的股价反应和财务业绩变化。

youdao