Module 1:
Database System
 Overview

Introduction

Traditional File Based System

Database Approach

Roles in Database Environment

The History of Database System

Advantages and Disadvantages of Database Systems
Introduction

Database is now such an integral part of our day to day
life.

We can consider a


Database to be collection of related data .
DBMS to be a software that manages and controls
access to the database
 Traditional File Based System

A Collection of application programs that perform
services for the end users such as the production of
reports. Each file define and manages its own data
Data Entry
And Reports
File handling
Routine
Sale File
File Definition
Sale Computer
Data Entry
And Reports
File handling
Routine
File Definition
Contract Computer
Contract File
Limitations of the File-Base Approach

Separation and isolation of data

Duplication of data

Data dependence

Incompatibility of data

Fixed queries
Database Approach

A shared collection of logically related data (and a
description of this data), design to meet the information
needs an organization

DBMS

A software system that enables users to define, create
and maintain database and which provides controlled
access to this database.

DDL

DML

DCL
Components of DBMS Environment

Hardware

Software

Data

Procedures

People
Data
Hardware
Software
Procedures
People
Bridge
Machine
Human
Roles in Database Environment

Data and Database Administrator


Data Administrator (DA)
Planning
Database Administrator (DBA)
Physical

Database Designer

Application programmers

End User

Native User

Sophisticated User
The History of Database System

1960s Apollo moon-landing project need a database

North American Aviation(Now Rockwell International)
develop a software GUAM(Generalized Update Access
Method) based on smaller components come together
as a part of large component. This structure also known
as hieratical structure.

Mid 1960s IBM joined NAA to develop GUAM now known
as IMS (Information management system)

Mid 1960s another significant development IDS
(Integrated Data Store) from General Electric.
The History of Database System

1967 US govt. assigned a task to Database Task Group
(DBTG) to define standard.

DBTG released a first report which identified three
components in 1969.
Network Schema---Database definition seen by the DBA
(DDL)
Subschema---seen by user and application program (DDL)
Data Management language—data characteristics (DML)
The History of Database System

This report was not formally adopted by ANSI(American National
Standards Institute)

1970, E.F Codd of IBM produce a concept of relation data model

It has two major development



RDBMS in 1980s DB2 and SQL/DS from IBM and Oracle from
Oracle Corporation. (First Generation)
Second Generation (RDBMS)


SQL (Structure Query Language)
Paradox and dBase IV from Borland, Access from Microsoft, FoxPro
and R:base from Microrim.
Third Generation

Object Oriented Data Model (OODM)

Extended Relation Data Model (ERDM)
Advantages and Disadvantages of Database Systems
Advantages

Control of data redundancy

Data consistency

More information from the same amount of data

Sharing of data

Improved data integrity

Improved security

Enforcement of standards

Economy of scale
Advantages and Disadvantages of Database Systems
Advantages

Balanced conflating requirements

Improved data accessibility and responsiveness

Increased productivity

Improved maintenance through data independence

Increased concurrency

Improved backup and recovery services
Advantages and Disadvantages of Database Systems
Disadvantages

Complexity

Size

Cost of DBMS

Additional Hardware cost

Cost of Conversion

Performance

High impact of failure