Students Learn About:
- a transaction – a series of events important to an organisation that involve
- a request
- an acknowledgement
- an action
- an outcome
- the components of a transaction processing system, including:
- purpose
- data
- information technology
- processes
- participants
- batch transaction processing – the collection and storage of data for processing at a scheduled time or when there is sufficient data
- real time transaction processing – the immediate processing of data
- the significance of data validation in transaction processing
- the historical significance of transaction processing as the first type of information systems
Students Learn To:
- recognise and describe a transaction
- identify, describe and use a batch transaction processing system
- distinguish between the storage of collected data and the storage of processed data in a batch system
- identify, describe and use a real time transaction processing system
- compare and contrast batch and real time transaction processing
- analyse an existing transaction processing system to determine its strengths and weaknesses
- design and implement procedures for validating entered data
- assess the work routine of a clerk in a manual transaction system to determine its suitability for automation
- identify participants, data/information and information technology for the given types of transaction processing systems
- describe the relationships between participants, data/information and information technology for the given types of transaction processing systems
Characteristics of a TPS
Transaction processing systems (TPSs) collect, store, modify and retrieve the transactions of an organisation. A transaction is an event that generates or modifies data that is eventually stored in an information system. Transaction -
A unit of work composed of multiple events that must all succeed or must all fail. Events perform actions that create and/or modify data.
Some examples of TPSs are - selling goods using a point-of-sale (POS) system,
- processing credit card payments, or
- making a motel reservation.
TPS's differ in character from other types of information systems in that they directly support business operations. - They must be designed in conjunction with the organisation’s procedures.
- The transaction data obtained from a TPS is stored in an information system and processed using a range of application software.
- It usually involves updating a database to reflect changes to the transaction data.
The main information processes of a TPS are collecting and storage. If a TPS is used to record a sale and generate a receipt, the transaction data is collected at the POS terminal and then stored using an online database. Managing the success or failure of transactions is an essential process performed during transaction processing. Transaction processing systems include mechanisms for ensuring events can be completed successfully, but not yet permanently. Essentially the transaction processing system - requests that each event occur and
- receives a response indicating that the actions performed are guaranteed to succeed or have failed.
- If a successful response is received for all events then the transaction as a whole can be “committed”, meaning each event is requested to store its data changes permanently within the appropriate databases or systems.
- If one or more events have failed then the transaction is “rolled back”, meaning each event is requested to abort all actions.
- In response each event sends an acknowledgement to confirm they have performed the request.
The four important characteristics of a TPS are rapid response, reliability, inflexibility and controlled processing. - 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 of 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 of 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 transaction 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.
A TPS minimises the organisation’s costs by reducing the number of times that data must be handled and by providing timely updates to the database.There are two types of transaction processing: batch transaction processing and real-time transaction processing
HISTORICAL SIGNIFICANCE OF TRANSACTION PROCESSING- The operations performed by transaction processing systems were up until the 1950s performed solely by clerks using manual processes.
- Early computers were originally developed to solve scientific and mathematical problems for government and military.
- It was during the 1950s that the application of computers to business and financial
- Prior to the 1980s it was common for complete transaction processing applications to be developed (often in Cobol) for each individual organisation.
- During the 1980s database management systems emerged to manage and control access to databases.
- Today most transaction processing systems are based on one or more relational database management systems (RDBMS) with client applications being written to meet an organisation’s specific needs.
Today large enterprises such as banks, large corporations and government departments use transaction processing monitor (TPM) software to manage transactions across a variety of databases and applications of different types, operated by different organisations and in different locations. Common TPMs in use include IBM’s CICS and Encina products, BEA System’s Tuxedo software and more recently Microsoft Transaction Server (MTS). TPMs are an example of enterprise systems as they manage critical data and processes across an entire organisation.
Manual Systems vs Automated Transaction Processing Systems
Processing of manual transactions almost always follows a strict sequence of events. - Each event must be acknowledged as complete before the next commences and if any event fails then the entire transaction is aborted.
- In manual systems, events are performed by clerks and other personnel according to strict predefined rules.
- Indeed in large organisation’s it is common for each clerk to repetitively perform just one of the events within each transaction.
- The transaction is handed onto the next clerk responsible for the next event in the sequence.
- The strict sequence and rules of such transactions make them particularly well suited to automation using computers.
;) Manual system strengths: - • Minimal start-up costs – little or no initial capital expenditure.
- • Minimal training time and costs.
- • Quick response to changing requirements.
- • Well suited to small organisations where participants have time and fulfil multiple roles.
- • Responds well to human insight and intuition.
Manual system weaknesses: - • Analysis of historical data is difficult and time consuming.
- • Transactions take considerably longer to process.
- • Difficult to rigidly enforce transaction rules and sequences.
- • Redundant or duplicate data is a feature of most manual systems.
- • Some human errors are to be expected.
- • System becomes more and more difficult to manage as it grows.
- • Making backups of data is difficult and is rarely, if ever, performed for all data.
Automated transaction processing strengths: - • Much faster transaction processing.
- • Less repetitive work for participants.
- • Enforces the sequence and rules for each transaction.
- • Calculation errors are virtually eliminated.
- • Ability to integrate transaction processing with outside organisations.
- • Historical data available for statistical and financial analysis.
- • Backups easily made and restored if system fails.
- • System easily grows as transaction processing needs grow.
Weaknesses of automated transaction processing: - • Significant start-up costs to purchase information technology.
- • Extensive training required to operate the system.
- • Changes to requirements often require specialised expertise to implement.
- • Rigidly enforces existing transaction rules and sequences for all data.
- • Less total work for humans resulting in lower employment.
- • Reliance on information technology – failure of one or components can cripple the entire system.
Information Systems Components -
What makes a Transaction Processing System?
The components of a TPS, like all information systems, include purpose, information processes, participants, data/information and information technology. Though, the most important component of a TPS is the people. Without people the system does not have customers and without customers it does not have a function to perform.
Users are the people that use the information that is stored by the TPS and may include people that are employees of a company that owns the TPS. The information provided from the TPS may be used for other information systems such as stock control and marketing.
Purpose is a statement identifying who the information system is for and what it needs to achieve. In TPS, it depends on the business. An example of a real-time transaction processing is motel reservation systems and the purpose of the TPS may be to sell a room.
Information processes are computer based and non-computer based factors that the TPS should have or can do. In the example of a motel reservation system, it may include collecting customer details, search database, update transactions and display room information.
Participants are people who will enter the data. They may include data entry operators, people working at checkouts, basically anyone carrying out the tasks required to process the data. In the motel reservation system example, it may be the motel staff or the manager.
Data/Information is the raw material used by information processes. In the motel reservation example, it could include confirmation, customer account and room details.
Information Technology is hardware and software used in information processes and in the motel reservation system example; it could be a personal computer, DBMS and EFTPOS.
Transaction processing monitor A transaction processing monitor (TP monitor) is software that allows the transaction processing application programs to run efficiently. It manages the sequence of events that are part of a transaction. - A TP monitor provides a standard interface between the input devices (such as terminals), the transaction processing application programs, and the DBMS.
- It also provides data security by ensuring that transactions do not get lost or corrupted.
- A TP monitor is used in conjunction with a particular operating system.
Transaction processing monitors (TPMs) are software applications that coordinate the transaction processing of large transaction processing systems. Fig 4.6 describes the general software architecture of transaction processing systems that include transaction processing monitors. These large systems commonly include many database servers that may access the same logical database or may access different databases. In addition transaction processing monitoring applications can connect to systems operated by other organisations.
Each server or system has its own resource manager (refer Fig 4.6) that makes available resources to the TPM. A resource manager is essentially a software product that provides an interface between the resource and the transaction processing monitor.
Introduction to TPS.pptIntroduction to TPS.ppt
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