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DISTRIBUTED DATABASES

By: Neha Sharma09ITMG2043SE


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CONTENTS_____________________________________________________________________________________________________________________________________________________

Introduction Objective of proposed Work Review of literature Survey

a) Ddbb) Ddbmsc) Evolution of ddbd) Advantages

e) Disadvantagesf) Goalsg) Technical Issues

Tentative plan of the work


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OBJECTIVE OF PROPOSED WORK_____________________________________________________________________________________________________________________________________________________

In this Thesis

1) I will work on Fundamentals Distributed

databases, their advantages and disadvantages.2) Will find out various design andimplementation issues.

3) How these issues can be resolved usin various

Transparency Feature.


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INTRODUCTION_____________________________________________________________________________________________________________________________________________________

Adatabase is a system intended to organize,store, and retrieve large amounts of data easily.

It consists of an organized collection of data for

one or more uses. ADatabase Management System (DBMS)

is a set of computer programs that controls thecreation, maintenance, and the use of a database

It allows organizations to place control ofdatabase


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DDB_____________________________________________________________________________________________________________________________________________________

Distributed database is a collection of data thatlogically belongs to the same system but isspread over the sites of a computer network.

Collection of data with different parts under thecontrol of separate DBMSs running onindependent computer systems.

Computers are interconnected


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DDBMS_____________________________________________________________________________________________________________________________________________________

A distributed database management system(DDBMS) is the software :

that manages the DDB

provides access mechanisms that make thedistribution transparent to the user.

Governs storage and processing of logicallyrelated data over interconnected computersystems


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EVOLUTION_____________________________________________________________________________________________________________________________________________________

Centralized database required that corporatedata be stored in a single central site.

Dynamic business environment and centralizeddatabases shortcomings spawned a demand orapplications based on data access from differentsources at multiple locations.

The need to share data that is dispersed cannotbe satisfied by centralize DBMS.


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Distributed database system is the union of what

appear to be two diametrically opposed approaches todata processing: database systems and computernetwork

Computer networks promote a mode of work thatgoes against centralization

Objective of DB technology is integration notcentralization


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ADVANTAGES______________________________________________________________________________________________________________________________________________________________________________

Improved performance, reliability, andavailability

Increased efficiency

Data are located near greatest demand site

Faster data access

Faster data processing

Growth facilitation Improved communications

Reduced operating costs

Less danger of a single-point failure


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DISADVANTAGES______________________________________________________________________________________________________________________________________________________________________________

Complexity of management and control

Security

Lack of standards

Increased storage requirements

Greater difficulty in managing the dataenvironment

Increased training cost


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GOALS

The distributed nature of the database is hiddenfrom users , as if the data were locally availableand controlled by a single DBMS.

Designing efficient distributed database

Highly scalable with no critical failure points.

Uniform access to physically distributed data, no

mater what the distance between the accesslocation and places data resides.


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TECHNICAL ISSUES_____________________________________________________________________________________________________________________________________________________

1. Distributeddatabase design Howto fragment the data? Partitioned data vs. replicated data and duplication of data.

2. Distributedquery processing Design algorithms that analyze queries and convert them into a series of data manipulation

operations Distribution of data, communication costs, etc. has to be considered Find optimal query plans

3. Distributed concurrency control Synchronization of concurrent accesses such that the integrity of the DB is maintained Integrity of multiple copies of (parts of) the DB have to be considered.

4. Distributeddeadlock management Deadlock management: prevention, avoidance, detection/recovery DDB

5. Reliability

How to make the system resilient to failures Atomicity and Durability

6. Security

7. Scalability


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So..

All these issues can be resolved using Transparencyfeatures in DDB.

Transaction transparency(Concurrency) Failure Transparency Performance transparency Distribution transparency(location transparency) Replication transparency

Fragmentation transparency Heterogeneity transparency


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TENTATIVE PLAN OF WORK_____________________________________________________________________________________________________________________________________________________

Now, The aim of my work is to study in detail :

a) All the technical issues stated above

b) How these issues can be resolved using abovetransparency Features.


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Thanks

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