数据库事务 定义 ​ 1）数据库事务是构成单一逻辑工作单元的操作集合，包含一个或多个数据库操作，这些操作构成一个逻辑上的整体。 ​ 2）一个典型的数据库事务如下所示 1234BEGIN TRANSACTION ...

进程与线程的关系 进程是操作系统资源分配的基本单位 线程是cpu调度和分配的基本单位 一个进程可以有多个线程 进程在执行过程中拥有独立的内存单元，而多个线程共享内存，从而极大地提高了程序的运行效率 线程的划分尺度小于进程，使得多线程程...

集合的分类123456789101112131415161718Collection 接口的接口 对象的集合（单列集合）├——-List 接口：元素按进入先后有序保存，可重复│—————-├ LinkedList 接口实现类， 链表，...

  Chinese families attach great importance to their children’s education. Many parents believe that they ...

Dear Tom,  On hearing that you are planning to teach English in China and inquire which city to work in, ...

  In recent years, more and more cities in China have begun to build subways. The development of subways ...

  As we all know, proficiency in speaking is necessary for us to become well-rounded communicators. Howev...

  Buses used to be the main means of transportation for the Chinese people. In recent years, with the num...

  As the most productive and communicative way to express ourselves, writing is attached great importance...

  In the past, traveling by plane was unimaginable for most Chinese people. Today, with development of Ch...