DATABASE MANAGEMENT SYSTEMSLecture 1

INTRODUCTION Data:

Collection of Raw Facts and Figures Raw Data not Processed to get ACTUAL MEANING Data can be Numeric (Contains Numbers) Alphabetic (Contains Alphabets) Alphanumeric (Contains Numbers, Alphabets

and Symbols) Image (Graphs, Diagrams) Sound or Audio (Voice) Video (Images Played at Very High

Speeds) Initially Meaningless But Very Important For Organization Example: Data Submitted By Students in the Application

Form is Initially Meaningless for the Vice Chancellor of the University until the Merit Lists are Generated from it.

INTRODUCTIONInformation:

Processed Form of Data More Meaningful Used For Decision Making Raw Data is Processed to get INFORMATION

DATA PROCESSING INFORMATION

When Merit Lists are generated from the DATA collected in the Application Form of University, then it is converted into INFORMATION.

INFORMATION can be further Processed INFORMATION can be Stored

DATABASE Definition:

ORGANIZED Collection of RELATED Records This Collection is Stored in EFFICIENT and COMPACT

Manner ORGANIZED: Means DATA is Stored in a way for User to

use it easily RELATED: Means DATA is Collected for a Particular Event EVENT: Means for Particular Thing Example: Admission Time in University is an

EVENT at which DATA of all Students seeking Admission is Collected.

EFFICIENT: Means Data is Stored in a way that it can be Saved and Retrieved Easily

COMPACT: Means DATA is Stored in a way to take Minimum Storage Space on Disk (Compressed Form)

DATABASE----EXAMPLE

Form No

Last Name D.O.B OBT. Marks

TOT. Marks

Applied In

65887 Ali Raza 05-05-1986 530 800 CS

65888 Ijaz Ahmer 09-10-1988 547 800 PHY

65889 Naveed Aslam 02-04-1987 489 800 BIO-CHEM

65890 Muhammad Irfan

01-04-1988 529 800 CHEM

65891 Waqas Ali 02-02-1989 435 800 BIOSample Database of Students Applied In Different Disciplines During Admissions in the University

Examples: Telephone Directory Student

Record Student Attendance Question Bank Result Reports Library Section Accounts Section

Employee List

DATABASE MANAGEMENT SYSTEMSDefinition:

A System used to Create and Manage Databases

It is a Set of SoftwareFacilities Provided by DBMS:

Defining Structure of Database Defining Integrity Checks Store Data on Storage Medium Data Compression Data Security Manages to INSERT, UPDATE, DELETE and

SELECT Data from Database by providing 4GL or a Non-Procedural Language which is SQL

NEED OF DATABASE MANAGEMENT SYSTEMS

File Processing

System

Was

FILE PROCESSING SYSTEM One of the First Computer Based Data Handling

Method Used in Old Organizations Organization is divided into different Departments In File Processing System each Department has its own

Set of Files and Set of Applications for Inserting and Managing Data in the Files Each of the Files has its own Format

Applications were designed for specific Formats The Applications were only used for the File Format for

which it was designed One Application can not be applied to any other File

Format This means that the Process of Upgrading the Format

of Files was very difficult because Applications must also have to be changed accordingly

This makes it a tedious and lengthy process Data in one File was not related to Data in another File So the if the Requirement was to Extract Data from

Different Files was very difficult

MAIN PROBLEMS OF FILE PROCESSING SYSTEM

Data Redundancy or Data Replication Data Inconsistency Data Isolation Data Integrity Application and Data Dependence Atomicity Problem (Related to

Transactions) Security Problem Increased Development Time No Way to Control Access Maintenance Problem