ACCESS学习日记
ACCESS学习日记
一、 ACCESS 的六种对象
a) 表是数据库的基本对象,其它几种对象都基于它而产生.
b) 查询: 可以按照索引查找需要的记录; 可以按要求筛选记录; 连接若干字段组成新表.
c) 窗体提供了一种方便的浏览,输入及更改数据的窗口.
d) 报表:数据分类汇总,打印.
e) 宏:相当于批处理,执行一系列操作
f) 模块:功能与宏相似,只是更加精细,编程.
二、 六种对象,三种类型
a) 表和查询: 数据的来源和基础
b) 窗体和报表:用于显示和打印
c) 宏和模块:主要用于控制.
d) 补充:通过数据访问页访问数据(一种网页)
a) 表的概念:
i. 表的属性; 表的记录; 表的分量;
ii. 对记录的操作: 投影和选择;
iii. 表与表之间可以建立连接;
b) 表的设计原则
i. 表的功能要单一;(符合范式)
ii. 字段唯一;
iii. 记录唯一性(不存在完全一样的记录)
iv. 功能相关性(不包含无关属性)
v. 字段无关性:对某一字段的修改不应该影响其它字段的数据(解决办法通常是分割表)
c) 创建数据库(通过模板; 使用向导创建表; 用表设计器创建表;)
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