1. Introduction to Database J.G. Zheng May 14 th 2008

2. Overview What is database? Why database? Advantages and disadvantages to use database Functions and components of database systems

3. Sample Business Data An example of order form

4. Application Centered Approach Past data depended on applications (programs) to define their meanings and structures For example: What does these piece of data mean? 2161710230302BV0602079495 21617-102303-02-BV06-02-079495

5. Data File Approach (Figure 1.1 on page 3)

6. Data File Problems The data file approach is problematic dealing with large quantities of data Redundancy increases input and maintenance efforts wastes space and slows down processing may introduce inconsistencies to the data Not scalable concurrency issue Limited security Size limitations

7. Database Approach Database processing features the separation of data from programs (data independence, or self-described) It provides a centralized management of data Data sharing Data management

8. Advantages of Database

9. Disadvantages of Database

10. Database Systems Basic elements of a database system

11. Database Management System DBMS serves as a controller (gatekeeper) for database, managing and controlling database activities reading, updating and deleting data data backup and recovery creating and maintaining tables and other structures controlling concurrency and consistency providing security DBMS uses SQL as command language (chapter 3)

12. Applications/Programs Applications (programs) serve as intermediaries between users and DBMS, to help users perform information processing tasks Functions include: Providing an easy-to-use user interface (menu, form, report) Executing business logic/process (calculation, analysis) …

13. Popular Products Desktop database system / personal database Microsoft Access Organizational database systems 1 Oracle (Oracle, 39.8% ) DB2 (IBM, 31.3% ) SQL Server (Microsoft, 12.1%) MySQL (Sun Microsystems) Most popular database for the web 1 market share data are from IDC 2003 Report

14. Organizational Database System

15. Summary Database processing is a centralized way to manage data (data centered) Database processing has great advantages when dealing with large quantities of data Database system consists of user, application, DBMS and database

16. Good Resources A short database history http://math.hws.edu/vaughn/cpsc/343/2003/history.html Largest databases http://www.wintercorp.com