DBMS Updated

8/8/2019 DBMS Updated

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Submitted to Prof. Lukman Patel


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QURESHI MOHAMMAD AAMIR

SYED ALMAS MUSHTAQUE AHMED

AZMI ZEESHAN AHMED ADEEL

SHEIKH RESHMA ISMAIL

VAGHER HUSSAIN ASGARALI

KHAN AASIM IRSHAD

SURYA MOHD.ALTAF ABDUL


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A DBMS is a collection of interrelated data and a set ofprograms to access those data.

Database Collection of data. It contains information which is

relevant to an enterprise.

Primary goal of DBMS is to provide a way to store andretrieve DB information that is both convenient andefficient.

DBMS has evolved from a specialized computerapplication to a central component of a moderncomputing environment and as a result knowledgeabout DB system has become an essential part of an

educating in computer science.


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DB system are designed to manage largebodies of information.

Management of data involves both-

1)Defining structure for storage of information.

2)Providing mechanism for the manipulationof the information.

In addition DB system must ensure the safety

of information stored, dispite system crashes orattempts at un-authorized access.


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Banking Credit card

Airlines

Universities Credit card transactions

Telecommunication

Finance

Sales

Manufacturing

Human Resources


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Data redundancy and inconsistency.

Difficulty in accessing data.

Data isolation.

Integrity problems.

Atomicity problems.

Concurrent access anomalies.

Security problems.


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Software

Hardware

Data

User

Procedures


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DataAbstraction is used to hidecomplexity levels. i.e,

-Physical Level

-Logical Level

-View Level

Database Schema

It is the overall design or structure ofthe database.

Physical Schema

Conceptual Schema

ExternalSchema 1

ExternalSchema 3

ExternalSchema 2


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The data independence is the ability tochange the schema at one level of a databasesystem with out changing the schema at ahigher level.

One of the most important benefits of usinga DBMS!

Logical data independence: Protection fromchanges in logicalstructure of data.

Physical data independence: Protection fromchanges in physicalstructure of data.


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Different and conflicting versions of the samedata

e.g. Employee database:personal info payroll

- ID - ID (relating parameter)

- name - name (causes redundancy)

- address - gross salary


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Schema definition

Storage structure and access-method definition

Schema and physical-organizationmodification

Granting of authorization for data access

Routine maintenance


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DDL(DATADEFINITIONLANGUAGE)

DML(DATAMANIPULATIONLANGUAGE

Storage access structure

Structure of database Schemas are defined

using DDL.

Retrieving data

Adding Data Deleting Data

Modifying data

Updating Data


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Two-tier architecture: E.g. client programs using ODBC/JDBCto communicate with a database

Three-tier architecture: E.g. web-based applications, andapplications built using middleware


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Adata model is a collection of concepts for

describing data.

Aschema is a description of a particular collection

of data, using the given data model.

The relational model of data is the most widely

used model today.

M

ain concept:r

elation, basically a table with rows andcolumns.

Every relation has a schema, which describes the

columns, or fields.


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It is important to design the database in such a way that:It is important to design the database in such a way that:

A specific item can be reached easilyA specific item can be reached easily

The database can respond to the usersThe database can respond to the users

different questions easilydifferent questions easily

The database occupies minimum storage spaceThe database occupies minimum storage space

The database contains no unnecessary dataThe database contains no unnecessary data

Data can be added and updated easilyData can be added and updated easilywithout causing mistakeswithout causing mistakes


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Documents

DBMS Updated