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Pankaj Joge

pankaj.joge@dishamail.com

Mobile # 9617661234

mailto:pankaj.joge@dishamail.commailto:pankaj.joge@dishamail.com

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WHAT IS DATABASE?

Collection of Coherent data with some

Inherent meaning.

Database are designed, built and

populated with data for a specific purpose

Example: Postal Address and what else?

Difference between Address Book and

Postal Address

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Examples of database in real life

A telephone book

T.V. Guide

Airline reservation system

Motor vehicle registration records

Papers in your filing cabinet

Files on your computer.

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DATABASE MANAGEMENT SYSTEM

System that helps in managing data

Allows inserting, updating, deleting and processing.

Examples: Oracle, Ingress, Sybase, Dbase 3+, Foxbase,

Foxpro, MS Access, Dataease, Dataflex and so on..

Objects, their attributes and the relationship between

them (that are of interest to us) are stored in the database

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DBMS Vs File Management System

A FMS is how data is stored on computer in Drives

By placing data electronically in files. These files are then stored in specific locations on the

hard disk (directories).

If the user wishes to perform some operation he has to

scroll through all the data by himself in order to see thedata he is interested in.

A user has to know where he put the files that containthe data and also if there are multiple files.

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DBMS Vs File Management System

A Database Management System intends to :

Remove the burden of manually locating data.

Having to scroll through it by allowing the user tocreate a logical structure for the data beforehand.

Allowing the user to place the data in the database thatthe DBMS is managing.

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Functions of DBMS

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DATA DEFINITION

DATA MAINTENANCE

DATA MANIPULATION

DATA DISPLAY

DATA INTEGRITY

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Benefits of DBMS

Establishes Relationships between Data

No data inconsistencies

Reduction of data redundancy Data can be shared by single or multiple users

Standards can be set and followed

Data integrity can be maintained

Security of the data can be simply implemented

Data independence can be achieved

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Shortcomings

COST

COMPLEXITY

Problems Associated With

CENTRALISATION

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Database Architecture

A2-Tier Architecture

The server holds both the application and the data.

The application resides in the server.

Server will have more processing power and disk space .

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CLIENT SERVER

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Database Architecture

A3-Tier Architecture

The data and applications are split onto separate servers.

The client is a front end simply requesting & displayingdata.

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CLIENT DATABASESERVER

APPLICATION

SERVER

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DATABASE MODELS

Databases appeared in the late 1960s, at a time whenthe need for a flexible information managementsystem had arisen.

There are three models of DBMS, which aredistinguished based on how they represent the data

contained

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RELATIONAL DBMS

DBMS that is based on the relational model asintroduced by Dr. Edgar F. Codd

Stores data in the form of related tables

Powerful because they require few assumptions abouthow data is related or how it will be extracted from thedatabase

Same database can be viewed in many different ways

Single database can be spread across several tables

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