第1章 数据库概述

1.1.1 Characteristics of the Application Systems Centered on Large Data
The application systems centered on large data: examples: book management system airline reservation system、 GIS、CAD/CAM、OAS Characteristics : Involve large quantity data Need to save data in the computers in a long periods Shared data by many applications
• One of the most widely used technology in compute science • The most new and effective technology for managing information
Applications of the database technology:
…
Application n
File system
…
File n
Examble
App. A1 Student information management
Data File
Student information
App. A2 Student choosing course management
Student information Course information Student-course information
Database and Functional Analysis
Qiao Mei Dept. of Computer Science and technology, Tianjin University of technology
Introduction About the Course Database technology:
• Small transaction process system : various kinds of MISs ( Mamagement Information System ) • Large information systems: GIS 、OAS、CAD/CAM • Online analysis process (OLAP）、data mining (DM)
Homeworks, tests and experiments（20%） Midterm exam (30%) Final exam (50%)
Chapter 1 Introduction to Database
Chapter 1 - Objectives
Evolution of data management technology Database and DataBase Management System The advantages of database technology in data management Components of a database system
When system crashes we may loose data Password-based authorization insufficient No control over data correctness and consistency
Concurrency: limited protection
Course Format
Teaching hours arrangement: plan ： 48 teaching hours include: lecture: 40 teaching hours experiment: 8 teaching hours Grading and evaluation:
Intruduction About the Course Three main aspects of database technology： • Database basic principles,technology and methods
• DataBase Management System (DBMS) ORACLE、 DB2 、MS SQL_SERVER • Application development tools C#、PB、VB、Delphi、ASP、JSP 、JAVA
1.1.2 Management Data Using File Management System
Managing data using file system:
Time: the late of 50’s to the middle of 60’s of 20 century Approach: Application 1 Application 2 File 1 File 2
System Catalog
Repository of information (metadata) describing the data in the database. Typically stores:
names, types, and sizes of data items; constraints on the data; names of authorized users; data items accessible by a user and the type of access; usage statistics.
Need to worry about interfering with other user
1.1.3 Database Approach
Arose because:
Large workload in application program development and maintenance because programs and data are highly dependent. No control over access and manipulation of data beyond that imposed by application programs.
Fixed Query/update
Programs are written to satisfy particular functions. Any new requirement needs a new program. Need to Worry about performance.
Problems of File-Based Approach No control over access and manipulation of data
DBMS
DBMS is a software system that enables users to define, create, maintain, and control access to the database. Functions of a DBMS:
Data definition (数据定义） provides Data Definition Language –DDL Data manipulation （数据操纵） provides Data Manipulation Language - DML Storage management （存储管理）
Data redundancy (Duplication of data)
Same data is held by different programs. Wasted space and potentially different values and/or different formats for the same item.
Characteristics of File-based Systems Collection of application programs that perform services for the end users (e.g. reports). Each program defines and manages its own data.
1.1 Evolution of Data Management
Technology
Characteristics of the application systems centered on managing large quantity data Characteristics of file-based systems Problems with file-based approach. Database and DBMS Advantages of database management system in managing data
Problems of File-Based Approach Data dependence
File structure is defined in the pr来自百度文库gram code. Require to rewrite program when data structure changed Programs are written in different languages, and so cannot easily access each other’s files.
Textbook and References
• 数据库系统基础教程（英文版 第二版）机械工业出版社 （Database Systems: The Complete Book, Hector GarciaMolina, Jeffrey D. Ullman, and Jennifer Widom, Prentice Hall, 2002.） • 数据库原理与应用 何玉洁 机械工业出版社 • 数据库系统概论（第四版）王珊 高等教育出版社 • 数据库系统——设计、实现与管理（英文版 第三版）电子工 业出版社。（Database Systems:A Practical Approach to Design,Implementation,and Management,Third edition,Thomas Connolly,Carolyn Begg, Pearson Education Limited,2002.
Result:
Database (DB) and Database Management System (DBMS) .
Database
DataBase (DB) is a Shared collection of
logically related data , data is organized according to a certain kind of model and can be shared by multi-user and has less data redundancy and higher data independence . System catalog (metadata) provides description of data to enable program–data independence. Logically related data comprises entities, attributes, and relationships of an organization’s information.
Problems of File-Based Approach Separation and isolation of data
Each program maintains its own set of data. Users of one program may be unaware of potentially useful data held by other programs.