Home Database Mysql Tutorial 数据库系统原理(一)数据库系统基本概念

数据库系统原理(一)数据库系统基本概念

Jun 07, 2016 pm 04:01 PM
principle basic concept database user system design

数据库设计人员与用户之间进行交流的工具。(工具) 逻辑模型: (1)表达了DB的整体逻辑结构,它是设计人员对整个应用项目数据库的全面描述。(整体) (2)是从数据库实现的观点出发,对数据建模。(观点) (3)独立于硬件,但依赖软件。(独立性) (4)

喀?喎?http://www.2cto.com/database/数据库设计人员与用户之间进行交流的工具。(工具)

逻辑模型:

(1)表达了DB的整体逻辑结构,它是设计人员对整个应用项目数据库的全面描述。(整体)

(2)是从数据库实现的观点出发,对数据建模。(观点)

(3)独立于硬件,但依赖软件。(独立性)

(4)是数据库设计人员与应用程序人员之间进行交流的工具。(工具)

外部模型:

(1)是逻辑模型的一个逻辑子集。(整观独工)

(2)独立于硬件,依赖于软件。(独立性)

(3)反映了用户使用数据库的观点。(观点)

联系:

几种模型乍看似不同,但其特点都是整体性、观点、工具、独立性四个方面。

总结:

当感觉“看不懂”时,继续往下看,只有往下看了,你才能找到他们之间的联系。不要拘于某一个细节。不谋全局者不足谋一域......把握宏观,寻找联系,编织知识网,才能让自己脑中的知识更系统化~~

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