DATABASE M ANAGEMENT SYSTEMS Lecture 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.

INTRODUCTION Information:  Processed Form of Data  More Meaningful  Used For Decision Making  Raw Data is Processed to get INFORMATION DATA PROCESSING INFORMATIO N  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 NameD.O.BOBT. Mark s TOT. Mark s Applied In 65887Ali Raza CS 65888Ijaz Ahmer PHY 65889Naveed Aslam BIO- CHEM 65890Muhammad Irfan CHEM 65891Waqas Ali BIO Sample 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 SYSTEMS Definition:  A System used to Create and Manage Databases  It is a Set of Software Facilities 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  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