DATABASE Management systems

1. DATABASE Management systems Lecture 1

2. 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.

3. INTRODUCTION Information:  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

4. 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)

5. DATABASE----EXAMPLE 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

6. 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

7. NEED OF DATABASE MANAGEMENT SYSTEMS Was File Processing System

8. 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

9. 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