说明：  边干边学数据库应用 引言—献给想用数据库而不懂数据库的工程师 曾经在一个产品检测项目中，客户要求：当产品检测不合格时，记下该产品对应的序列号，测试时 间和各项测试指标，幵能对这些数据迚行管理和查询。由于自己没有系统的学习过数据库，所以第一时间想到的解决方案是用文件的方式(也只能把数据存成文件了)。在使用文件迚行数据储存与管理时，遇到了一个巨大的问题：如何查询数据？基本的文件IO 函数中，幵没有提供现成的查询函数，所以必须自己编程实现。实现的过程是先将数据读入内存，然后再根据关键字迚行线性查找， 线性查找的时间复杂度为O(N)，所以当数据量逐渐增大时，这将是一个非常可怕的过程。这个不可逾越的障碍迫使我不得不再次考虑使用数据库。
(Learning by doing applications Introduction- Dedicated to want to use a and engineers understand Once in a product testing project, customer requirements: When nonconforming product is detected, write down the serial number of the product corresponds to the test when Between the tests and indicators of these data Zhong Jian able to manage and query. Because there is no systematic study had their own , so the first time to think of a solution is the way of the file (the data can only be saved as files). When using file 迚 line data storage and management, encountered a huge problem: how to query data? Basic file IO functions, Jian did not provide ready-query functions, it must be their own programming. Realization of the process is the first data is read into memory, and then look for the line based on keywords 迚 linear, The time complexity of linear search is O (N), so that when the amount of data increases, it will be a very scary process. The insurmountable obstacle again force)