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Data Base Management

By-

Mahendra Prasad

Meghna Manna

Shiva Prasad

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Data

Data are symbols which represent, describe

or record facts. Thus data are collection of

facts related to events, objects etc.

Data are in unorganised form but are able tobe organised into useful information.

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Examples of Data Sources

E-mails

Credit cardswipes

RFID tagsDigital video

surveillance

Radiology scans

Blogs

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Data, Information, Knowledge, Wisdom

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Managing Data

Difficulties in Managing Data

Amount of data increases

exponentially.

Data are scattered and collectedby many individuals using

various methods and devices.

Data come from many sources.

Data security, quality andintegrity are critical.

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Difficulties in Managing Data (continued)

An ever-increasing amount of data needs to be

considered in making organizational decisions.

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Traditional File management

Also known as traditional data management

or traditional file processing.

It involves sharing storing data into files which

can be accessed, manipulated, updated andworked.

Computer systems stores files on secondary

storage devices. Depend on the storage and

access methods, files can be classifies asunder:

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Sequential access file;

Indexed-sequential access file;

Direct access file.

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Problems in Traditional File

Management

Data Redundancy;

Lack of flexibility;

Atomicity Problem;

Lack of Security;

Lack of data sharing.

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Database Management System

(DBMS)

Database: Database is a collection of data,

integrated and organized into a single

comprehensive file system which is arranged to

minimize duplication of data and to provideconvenient access to data within that system to

satisfy a wide variety of user needs.

When an organization has a centrally

controlled and integrated collection of data, ithas a data base.

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Definition of DBMS

A database management system is simply the

software that permits an organization to centralize

data, manage them efficiently, and provide access

to the stored data by application programs.

The following are examples of database

applications:

Computerized library systems

Automated teller machines Flight reservation systems

Computerized parts inventory systems

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Characteristics of DBMS

DBMS has the capacity to store large amount

of data necessary forusers needs. They are

stored on direct accessible devices;

It has capacity to interrogating data files,retrieving, and modifying data and recording

the changes.

The data are combined to form operational

units to minimise the duplication of data and

increase access to all data in data base;

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Contd

The control in the system limits access to the

database and builds the confidentiality of data

in the database;

The advancement in the database enables toadd more data and program to the system.

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Objectives of DBMS

Complexity of an organisations information systemsis reduced through centralisation of datamanagement.

Data redundancy and inconsistency are reduced anddata security is increased by eliminating all isolatedfiles in which the same data elements are replaced.With the result, data management cost is reducedsignificantly.

Program data dependence is reduced by providingcentral control of data creation and definition.

Data, once stored, are accessed by multiusers. Thus,data collected for one purpose can be used to servevarious purposes as the need arise.

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Conceptual model of DBMS

Non

programming

user

Database

administrator

Programming

user

Database Definition

Database creation

Database redefinitionDatabase restructure

Integrity controls

Database Query

Language facility

Database

programming

language interface

Database

Application

program

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DBMS has following four components:

Database administrator;

Database users;

Database software;

Database.

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Database Management Systems

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Entity-Relationship Modeling

Database designers plan the database

design in a process called entity-

relationship (ER) modeling.

ER diagrams consists of entities, attributesand relationships.

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Entity-relationship diagram

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Customer AccountDepositor

Name

Identity

numberAddress

number Balance

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Student Database Example

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Normalization

Normalizationis a method for analyzing and

reducing a relational database to its most

streamlined form for:

Minimum redundancy Maximum data integrity

Best processing performance

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Non-Normalized Relation

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Normalizing the Database

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Normalizing the Database

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Normalization Produces Order

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Data Warehousing

Data warehouse

Data warehouses are organized by business

dimension or subject.

Data warehouses are multidimensional.

A Data Cube

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Relational Databases

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Multidimensional Database

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Equivalence Between Relational and

Multidimensional Databases

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Equivalence Between Relational and

Multidimensional Databases

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Equivalence Between Relational and

Multidimensional Databases

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Benefits of Data Warehousing

End users can access data quickly and easily

via Web browsers because they are located

in one place.

End users can conduct extensive analysiswith data in ways that may not have been

possible before.

End users have a consolidated view of

organizational data.

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