串口通讯程序，适用范围普及，而且使用方便，可以参考一下。-Serial communication program, scope of application of universal, and easy to use, you can reference.

这本书目的是给读者提供一个关系型数据库模型领域的背景。这是一本易读的和有实践练习的书。-Relational databases provide a powerful means by which to store and manipulate vast volumes of data. The design of such systems is based on the mathematics of relational theory, which was advanced in it