What exactly does "key" mean, in the context of B-Trees?
“关键”到底是什么意思，在b树吗？
2
Make sure you understand what types of queries they are useful for, and how their properties differ from those of B-trees.
大家一定要理解他们分别适合于哪种类型的查询，并且理解他们的属性是怎么有别于B树。
3
Each table consists of one B-tree that contains the data, although there can be many secondary index B-trees used to provide different views of the data.