一.概述 在Visual Studio 6.0中编写串口通讯程序,一般都使用Microsoft Communication Control(简称MSComm)的通讯控件,只要通 过对此控件的属性和事件进行相应编程操作,就可以轻松地实现串口通讯。但在Micr…
一. B-Tree Index 原理 官网说明: No index structure can satisfy all needs, but the self-balancing B-tree index comes closest to optimizing the performance of searches on large sets of data. Each B-tree node holds multiple keys and pointers. The m…
首先创建序列: create sequence 序列名 start with 1 increment by 1 nomaxvalue nocycle 其次创建触发器: create or replace trigger 触发器名 before insert on 表名称 for each rowbeginselect 序列名.nextval into:new.表的列名 from dual;end;…