Transaction Processing SystemThis is a featured page

Transaction Processing System - Management Information SystemsA Transaction Processing System (TPS) is a type of 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 an information system. To be considered a transaction processing system the computer must pass the ACID test.
From a technical perspective, a Transaction Processing System (or Transaction Processing Monitor) monitors transaction programs, a special kind of programs. The essence of a transaction program is that it manages data that must be left in a consistent state. E.g. if an electronic payment is made, the amount must be either both withdrawn from one account and added to the other, or none at all. In case of a failure preventing transaction completion, the partially executed transaction must be 'rolled back' by the TPS. While this type of integrity must be provided also for batch transaction processing, it is particularly important for online processing: if e.g. an airline seat reservation system is accessed by multiple operators, after an empty seat enquiry, the seat reservation data must be locked until the reservation is made, otherwise another user may get the impression a seat is still free while it is actually being booked at the time. Without proper transaction monitoring, double bookings may occur. Other transaction monitor functions include deadlock detection and resolution (deadlocks may be inevitable in certain cases of cross-dependence on data), and transaction logging (in 'journals') for 'forward recovery' in case of massive failures.
Transaction Processing is not limited to application programs. The 'journaled file system' provided with IBMs AIX Unix operating system employs similar techniques to maintain file system integrity, including a journal.
Features of Transaction Processing Systems

Rapid Response

Fast performance with a rapid response time is critical. Businesses cannot afford to have customers waiting for a TPS to respond, the turnaround time from the input of the transaction to the production for the output must be a few seconds or less.

Reliability

Many organisations rely heavily on their TPS; a breakdown will disrupt operations or even stop the business. For a TPS to be effective its failure rate must be very low. If a TPS does fail, then quick and accurate recovery must be possible. This makes well–designed backup and recovery procedures essential.

Inflexibility

A TPS wants every transaction to be processed in the same way regardless of the user, the customer or the time for day. If a TPS were flexible, there would be too many opportunities for non-standard operations, for example, a commercial airline needs to consistently accept airline reservations from a range of travel agents, accepting different transactions data from different travel agents would be a problem.

Controlled processing

The processing in a TPS must support an organisation's operations. For example if an organisation allocates roles and responsibilities to particular employees, then the TPS should enforce and maintain this requirement.

Storing and Retrieving Storing and retrieving information from a TPS must be efficient and effective. The data are stored in warehouses or other databases, the system must be well designed for its backup and recovery procedures.

Databases and files

The storage and retrieval of data must be accurate as it is used many times throughout the day. A database is a collection of data neatly organized, which stores the accounting and operational records in the database. Databases are always protective of their delicate data, so they usually have a restricted view of certain data. Databases are designed using hierarchical, network or relational structures; each structure is effective in its own sense.
  • Hierarchical structure: organises data in a series of levels, hence why it is called hierarchal. Its top to bottom like structure consists of nodes and branches; each child node has branches and is only linked to one higher level parent node.
  • Network structure: Similar to hierarchical, network structures also organizes data using nodes and branches. But, unlike hierarchical, each child node can be linked to multiple, higher parent nodes.
  • Relational structure: Unlike network and hierarchical, a relational database organises its data in a series of related tables. This gives flexibility as relationships between the tables are built.
The following features are included in real time transaction processing systems:
  • Good Data Placement: The database should be designed to access patterns of data from many simultaneous users.
  • Short transactions: Short transactions enables quick processing. This avoids concurrency and paces the systems.
  • Real-time backup: Backup should be scheduled between low times of activity to prevent lag of the server.
  • High normalisation: This lowers redundant information to increase the speed and improve concurrency, this also improves backups.
  • Archiving of historical data: Uncommonly used data are moved into other databases or backed up tables. This keeps tables small and also improves backup times.
  • Good hardware configuration: Hardware must be able to handle many users and provide quick response times.
In a TPS, there are 5 different types of files, the TPS uses the files to store and organise its transaction data:
  • Master file: Contains information about an organisation’s business situation. Most transactions and databases are stored in the master file.
  • Transaction file: It is the collection of transaction records. It helps to update the master file and also serves as audit trails and transaction history.
  • Report file: Contains data that has been formatted for presentation to a user.
  • Work file: temporary files in the system used during the processing.
  • Program file: Contains the instructions for the processing of data.


t0nee
t0nee
Latest page update: made by t0nee , Feb 26 2008, 2:02 AM EST (about this update About This Update t0nee Edited by t0nee

1 image added

view changes

- complete history)
Keyword tags: None
More Info: links to this page
There are no threads for this page.  Be the first to start a new thread.