Doing so helps conserve disk space and also improves the performance of queries that use navigational expressions.

这样做可以节省磁盘空间，还可以改进使用导航表达式的查询的性能。

youdao

Doing so helps conserve disk space and also improves the performance of queries that use navigational expressions.

这样做可以节省磁盘空间，还可以改进使用导航表达式的查询的性能。

youdao