WHAT IS DATA BASE?

A COMPLETE LECTURE ON INTRODUCTION TO DATABASE SYSTEMS.

1. LEARNING OUTCOMES At the end of this chapter, students should be able to: Explain what is data management Differentiate manual file system and computerised file system with database system Define database system, database and database management system List the functions, advantages and disadvantages of database management system

2. TOPIC OUTLINES Introduction 1.1 Manual File System 1.1.1 Disadvantages of Manual File System 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System 1.3 Database System 1.4 Database 1.4.1 Characteristics of Database 1.5 Database Management System 1.5.1 Functions of Database Management System 1.5.2 Advantages of Database Management System 1.5.3 Disadvantages of Database Management System

3. INTRODUCTION Are you being overwhelmed by too much data?

4. INTRODUCTION Not sure how to make sense of the data?

5. INTRODUCTION What you need is D ata M anagement

6. INTRODUCTION Generating Data Storing Data Retrieving Data Data management is a discipline that focuses on the proper way for Focus of this course

7. INTRODUCTION We will examine 3 ways for managing data Evolution of Data Management

8. 1.1 Manual File System A manual file system is a way of managing data using Pen and paper

9. 1.1 Manual File System Record data on paper. File paper away into folders and cabinets. Data Storage

10. 1.1 Manual File System Locate paper from cabinets and folders. Retrieve data from paper. Data Retrieval

11. As data collection increases 1.1 Manual File System 1.1.1 Disadvantages of Manual File System

12. 1.1 Manual File System Where is my data? 1.1.1 Disadvantages of Manual File System Keeping track and looking up data becomes much more difficult

13. 1.1 Manual File System Solution to Manual File System Replace Manual File System with Computerised File System

14. 1.2 Computerised File System A computerised file system is a way of managing data using Files Computer Programs

15. 1.2 Computerised File System Launch a program (e.g. Microsoft Excel) to input data. When you saved the data, the data gets stored in a computer file (e.g. Excel file . xls ). Data Storage

16. 1.2 Computerised File System Find a program that could open the computer file (e.g. Excel file . xls ). Launch the program (e.g. Microsoft Excel) to retrieve the data. Data Retrieval

17. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System Program Dependency Data Redundancy Complex administration Click on the boxes for explanation

18. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System CLOSE Program Dependency Different computer programs generates different computer files. Microsoft Excel Intuit QuickBooks (Accounting) NEXT

19. BACK 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System CLOSE Program Dependency To open a computer file, you need to have a program that can read and understand the computer file This limits data sharing as ONLY people with the correct programs can read data in the computer file Intuit QuickBooks (Accounting) Fail

20. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System Data Redundancy CLOSE NEXT (Click on Mary, then John) I need to access the data in a computer file. Why don’t I copy the file and email it to you End result There are now two files with the same data. Mary has a copy of the data and John has a copy of the data as well (i.e. Data Redundancy ) Mary John

21. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System CLOSE As a thief, I now have more chance to steal your data. I can try to steal from either Mary or John. Before, I can only steal from John Data redundancy leads to poor data security NEXT BACK Data Redundancy

22. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System CLOSE BACK What if I want to update the phone number of a customer? (Click on me for answer) I would have to update both John and Mary’s file. If I forgot to update Mary’s file, she would have access to old phone number while John the new phone number. This is known as data inconsistency Data redundancy leads to data inconsistency Data Redundancy

23. 1.2 Computerised File System 1.2.1 Disadvantages of Computerised File System Complex Administration As more and more files get created Managing the program dependency and data redundancy become more challenging CLOSE

24. 1.2 Computerised File System Solution to Computerised File System Database System Replace Computerised File System with Database System

25. 1.3 Database System Database Database System Database Management System (DBMS) What is Database System?

26. A database can be thought of as an electronic version of a filing cabinet Database is where all the data are stored 1.3 Database System Database

27. A DBMS can be thought of as a secretary who has sole access to the filing cabinet DBMS handles all data requests (i.e. data storage/retrieval) on behalf of programs DBMS 1.3 Database System

28. 1.3 Database System Database Database Management System (DBMS) Program 1 Program 2 Program 3 Program N Only DBMS has access to database Programs store/retrieve data through DBMS Data stored in the database are shared by all programs (i.e. no redundant data)

29. 1.3 Database System Data Storage DBMS Database Click on the numbered boxes for explanation 1 2 3

30. 1.3 Database System Click on the numbered boxes for explanation Program ask DBMS to store data X Data Storage DBMS Database 1 2 3

31. 1.3 Database System Click on the numbered boxes for explanation DBMS stores data in the database X Data Storage DBMS Database 1 2 3

32. 1.3 Database System Click on the numbered boxes for explanation DBMS informs program of successful data storage X Data Storage DBMS Database 1 2 3

33. 1.3 Database System Data Retrieval DBMS Database Click on the numbered boxes for explanation 1 2 4 3

34. 1.3 Database System Click on the numbered boxes for explanation Program ask DBMS to retrieve data X Data Retrieval DBMS Database 1 2 4 3