Group By Node

But it's perfect for us, because it means that nobody can work out what the system is doing by looking at one node, or even a group of nodes.

但是对我们而言却是极好的，因为这意味着没有人可以通过查看一个节点或者甚至一组节点计算出系统的具体作用。

The GROUP BY and SORT clauses in SQL allow for more structuring than the examples in this column have demonstrated, but XML node hierarchies can represent their results as well.

SQL 中的 GROUP BY 和 SORT 子句所顾及的比本专栏示例所演示的更具有结构性，但 XML 节点层次结构也可以表示它们的结果。

Simplicity: the program can use these node tests to select a group of elements based on their common group head element or type definition rather than enumerate all concrete element names one by one.

简单性：程序可以使用这些节点测试，选择基于共同组head元素或类型定义的一组元素，而不是逐一列举所有具体的元素名。