2 3 4 5
DB Design Overview Basic Processes of DB Design Requirements Analysis Conceptual Design Structure Design Conclusion
7.1 DB Design Overview
The definition of DB design
DBAS Life Cycle
Database Initial study( requirement analysis)
Analyse the company situation, define problems and constrains, define objectives, define scope and boundaries
信息要求
处理要求
Structured Analysis (结构化分析方法)
2．Decompose Functions and Data(分解处理功能和数据)
(1) Decompose Functions
将处理功能的具体内容分解为若干子功能
Translate ER into DBMS data model Eg. translate model into definitions for tables, views...
Schema Refinement
consistency, normalization
Physical design
The Method of DB Design
2.Different kinds of methods including:
New Orleans (新奥尔良法) Method based on E-R Model(基于E-R模型的数据库设计方法) 3NF Method(第三范式设计方法） Object Definition Language Method(面象对象的设计方法)
Basic Processes of DB Design
Preparation for DB Design 数据库设计的准备工作
Decide People Participating in DB Design
(选定参加设计的人)
1.系统分析人员、数据库设计人员(Analyser and Designer) 自始至终参与数据库设计
Database Design
Create the conceptual design Create the logical design Create the physical design
Implementation and loading
Install DBMS, create the database(s), load initial data
2.Carry Out The Two Jobs Simultaneously at All Stages, Consult Each Other, Supplement Each Other
Schemas in DB Design
数据库设计不同阶段形成的数据库各级模式
Schemas in DB Design 数据库的各级模式
Difficulties of RA
Make final users’ needs clear (确定用户最终需求)
Reபைடு நூலகம்sons:
Users lack for computer knowledge(用户缺少计算机知识) Designer lack for users’ professional knowledge (设计人员缺少用户的专业知识)
7.2 Requirements of Analysis (需求分析)
Tasks of RA(需求分析的任务）
1.Defining requirements
(详细调查现实世界要处理的对象, 如组织、部门、企业, 充分了解原系统)
2.Analyzing requirements(明确用户的各种需求)
需求分析和概念设计独立于任何数据库管理系统
逻辑设计和物理设计与选用的DBMS密切相关
Basic processes of DB Design
Mini-World View Requirements Collection and Analysis
Conceptual Design
Logic Design Physical Design
事务设计
应用设计
物理数据库设计 应用开发 子模式设计 系统调试 建立数据库
应 用 系 统 设 计
The Method of DB Design
1.Needs for the knowledge below:
Computer basic knowledge Principle and Method of Software Engineer 计算机的基础知识 软件工程的原理和方法
• Search string • Clicking on links
Outputs
Search results Web page
Processes
Search database for search string Retrieve web page
Data Storage
Key points of RA 需求分析的重点
Operation
Produce the required information flow
Maintenance and evolution
Introduce changes Make enhancements
7.1.3数据库设计的基本步骤
数据库设计分6个阶段
需求分析 概念结构设计 逻辑结构设计 物理结构设计 数据库实施 数据库运行和维护
Method and Technique of programming design 程序设计的方法和技巧 Database basic knowledge Database Design technology 数据库的基本知识 数据库设计技术 应用领域的知识
Knowledge in the specific field
DBAS Life Cycle(cont.)
Testing and evaluation
Test the database Fine-tune(adjust) the database Evaluate the database and its application programs
Inputs Outputs Processes Data Storage
3.Decide the function and boundaries of new system (确定 新系统的功能)
同时充分考虑今后可能的扩充和改变
Instance of
Inputs
Index page
Basic Data(基础数据)
1.collect、store 2.Update
bine data design and operation design: (数据设计和处理设计相结合)
结构和行为分离的设计
现实世 界
数据分析 功能模型 功能分析 功能说明
数 据 库 设 计
概念模型设计
逻辑数据库设计
2
data manipulation requirements(数据操作要求)：
store and manage all kinds of data objects in database
do some operations on data, eg. search ,add ,delete,alter
2. 用户和数据库管理员 (users and DBA)
主要参加需求分析和数据库的运行维护 3.应用开发人员（ Application programmers） 在系统实施阶段参与进来，负责编制程序和准备软硬件环境
DBAS Life Cycle
Database study Database design Implementation and loading Testing and evaluation Operation maintenance and evolution
Storage structures - optimize performance Distributed database design
数据设计和处理设计同时进行
图表
Two Key points in DB Design
1. Combine Data Design and Manipulation Design Closely
Basic processes of DB Design
Conceptual Design
High level description (often done ER model) Entity Relationship modelling and normalisation
DBMS software selection Logical design
2. Grasp the method of requirements
(掌握需求分析的方法)
analysis
3．Grasp the basic processes and method of conceptual design
(掌握概念结构设计的基本步骤和方法)
Lecture Outline
1
Database Design
Liu Xiufeng Information and technology school
Objectives for Students