The facade is a class that provides a setof methods that can create data objects from the back end, or provide some other business function.
虚包是包含一套方法的类，利用它，你可以从后台创建数据对象，或提供一些其它的业务功能。
2
A data warehouse will normally be presented as a setof tables, which requires an end user to have knowledge of what tables and columns are relevant and how to join the tables together.
数据仓库一般表示为一组表，它要求最终用户知道哪些表和列是相关的以及如何将表联结在一起。
3
When all the data have been written, set the eof (end-of-file) argument.