Database Management System

• Introduction• Database system• Hardware• Software• Data• Users• Review

Introduction• Data

– Raw fact and figures– Example

• Name, Roll number, invoice no.

• Information– Processed or more useful form of data– It helps in decision making process

Introduction• Information

– Example• Time Table, Merit List, Report Card, Marks

• Need of Information• Knowledge

– Information containing wisdom– Derived from fundamental processing and

organizing

Introduction• Difference b/w Data and Information

• Database– The related information when placed in an

organized form makes a database– Unorganized information has no meaning– Example

• Dictionary• Telephone directory• Address book

Introduction

Manual database and its problems

Traditional file processing system

Limitation of file processing system

Database and computers

Commonly performed operations on database• Insertion : to add new information. e.g. to insert new address in address book.

• Updation : to modify or edit the existing information.e.g. your friend has shifted a new place so his address would get

changed.

• Deletion : to remove or delete unwanted informatione.g. delete unwanted contacts in ur mobile phones

• retrieval operation : to view or retrieve the stored information.e.g. you have to find address of one of your old friend “abcd”

• Sort operation: arranging the information in a desired ascending or descending order etc.

Building blocks of a database

Columns : columns are similar to fields that is individuals items of data that we wish to store.

Rows : rows are similar to records as they contain data of multiple columns.

Tables : table is a logical group of columns.

Characteristics of database

• Organized/related• Shared• Permanent or persistence• Validity/integrity/correctness• Security• Consistency• Non-redundancy• Independence• Easily accessible• Recoverable• Flexible to change

Database system• Definition

– DBMS “System that allow users to define, create and maintain a database and provides controlled access to the data.”

– enable user to store, modify and extract information as per the requirement

• Intermediate layer

• Example– Computerized Library System– ATM– Flight reservation system– Railway reservation system etc.

• DBMS in market– Dbase, Foxpro, IMS and Oracle

Database system

• Components of DBMS Environment– Hardware– Software– Data– Users– Procedures

Database system

Hardware• Computer System• Storage devices• Input / Output devices• DB work on micro computer to large

mainframe• Hardware issues

– Designed system

Software• Software is actual DBMS• b/w physical data and users• Requests handled by DBMS• Provide simple interface• Mediator b/w database and user• Utilities(Report writers, application development,design aids

etc)

• Example– MS Access, Oracle an IBM DB2

Data• Most important component of DBMS• Bridge b/w Machine and User

Users• Different users can access data• Depending on their degree of expertise

users are classified in the following groups– Naïve Users (ATM user)

– Online Users– Application Programmers– Sophisticated Users– DBA

Advantages of DBMS

•Controlling redundancy

•Integrity can be enforced

•Inconsistency can be avoided

•Data can be shared

•Standards can be enforced

•Restricting unauthorized access

• Solving enterprise requirement than individual requirement

• Providing backup and recovery

• Cost of developing and maintaining system is lower

• Data model can be developed

• Concurrency control

Disadvantages of DBMS• Complexity• Size• Performance• Higher impact of a failure• Cost of DBMS• Additional hardware costs• Cost of conversion

Comparison of file management system with database management system

File management• Small system• Relatively cheep• Simple structure• Redundant data• Chances of inconsistency• No security• Isolated data• Often single user

DBMS• Large systems• Expensive• Complex structure• Reduced redundancy• Consistent• Security• Data can be shared• Multiple users