Group 1 Ppt of Tps

7/31/2019 Group 1 Ppt of Tps

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A transaction processing system is a typeof information system

TPSs collect, store, modify, and retrieve

the transactions of an organization. A transaction is an event that generates or

modifies data that is eventually stored in aninformation system. To be considered atransaction processing system the computermust pass the ACID test.
http://en.wikipedia.org/wiki/Management_information_systemhttp://en.wikipedia.org/wiki/Transaction_processinghttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/ACIDhttp://en.wikipedia.org/wiki/ACIDhttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Transaction_processinghttp://en.wikipedia.org/wiki/Management_information_systemhttp://en.wikipedia.org/wiki/Management_information_system


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Transaction Processing is not limited toapplication programs. The 'journaled filesystem' provided with IBMs AIX Unix

operating system employs similar techniquesto maintain file system integrity, including a

journal.


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A TP system is the computersystem both hardware and

software that hosts thetransaction programs. Thesoftware parts of a TP system

usually are structured in aspecial way. As you can seefrom Figure 1.2 , the TP system

has several main components.Different parts of theapplication execute in each ofthese components.


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Contrastedwith batchprocessing Real-time and

batch processing
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T.P.S

2.1 Rapidresponse

2.3 Inflexibility

2.4 Controlledprocessing

2.2 Reliability
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COMPONENTS

1.Input

4.Output

3.Storage

2.Processing


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A transactions changes to the state are atomic:either all happen or none happen. Thesechanges include database changes, messages,and actions on transducers.[2]

Atomicity
http://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_system


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Consistency

A transaction is a correcttransformation of the state. Theactions taken as a group do not

violate any of the integrityconstraints associated with thestate. This requires that the

transaction be a correctprogram![2]
http://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_system


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Isolation

Even though transactionsexecute concurrently, itappears to each transactionT, that others executed eitherbefore T or after T, but notboth.[2]
http://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_system


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Durability

Once a transactioncompletes successfully

(commits), its changes tothe state survive failures.[2]
http://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_systemhttp://en.wikipedia.org/wiki/Transaction_processing_system


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12

Evolution of Transaction

Processing Systems The basic components of a transaction

processing system can be found in single

user systems. The evolution of these systems provides a

convenient framework for introducing theirvarious features.


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Single-User System

Presentation Services - displays forms, handlesflow of information to/from screen

Application Services - implements user request,interacts with DBMS

ACID properties automatic (isolation is trivial)or not required (this is not really an enterprise)

presentation applicationservices services

DBMS

user module

centralized system


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Slide 3 of 30


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Single-User System

Presentation Services - displays forms, handlesflow of information to/from screen

Application Services - implements user request,interacts with DBMS

ACID properties automatic (isolation is trivial)or not required (this is not really an enterprise)

presentation applicationservices services

DBMS

user module

centralized system


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Heterogeneous vs.

Homogeneous TPSs

Homogeneous systems are composed of HWand SW modules of a single vendor Modules communicate through proprietary (often

unpublished) interfaces Hence, other vendor products cannot be included

Referred to asTP-Lite systems

Heterogeneous systems are composed of HWand SW modules of different vendors

Modules communicate through standard, publishedinterfaces

Referred to asTP-Heavy systems


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17

Architecture of a Web

Transaction ProcessingSystem

Web Server

ApplicationServer

Database Server

Interacts withclient

Executes theapplication

Hosts the database

The application mightbe a transactionprogram thatimplements thebusiness rules of theWeb service

Java servletreceivesmessages and callsprogram onapplication server


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We have now seen the reasons why we needtransaction processing systems. The advantages of

three-tier applications in creating scalable and robustapplications are made feasible by transactionprocessing systems. The ability to distribute thecomponents that make up applications amongst

separate servers without explicitly having to developfor that architecture is another advantage oftransaction server processing. Transactionprocessing systems also ensure that transactions areatomic, consistent, isolated, and durable. Thisalleviates the developer from having to supportthese characteristics explicitly.


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Documents

Group 1 Ppt of Tps