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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