提供一个进销存系统的范例代码，包括数据库建模、进货、库存、查询等功能管理。-Provide a sample code enters sells saves the system, including database modeling, replenish onr s stock, inventory management, query and other function.

简易进销存学习用 绝对私人开发,并非上网抄袭,(Simple enters sells saves the learning Absolute private development, not the Internet plagiarism,)