Transaction Processing SystemA
transaction processing system 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. 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 E.g. if an electronic payment is made, the amount must be both withdrawn from one account and added to the other; it cannot complete only one of those steps. Either both must occur, or neither. 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 inquiry, 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.
Contrasted with batch processing
Batch processing is not transaction processing. Batch processing involves processing several transactions at the same time, and the results of each transaction are not immediately available when the transaction is being entered;
[1] there is a time delay. Transactions are accumulated for a certain period (say for day) where updates are made especially after work.
Real-time and batch processing
There are a number of differences between
real-time and
batch processing. These are outlined below:
Each transaction in real-time processing is unique. It is not part of a group of transactions, even though those transactions are processed in the same manner. Transactions in real-time processing are stand-alone both in the entry to the system and also in the handling of output.
Real-time processing requires the master file to be available more often for updating and reference than batch processing. The database is not accessible all of the time for batch processing.
Real-time processing has fewer errors than batch processing, as transaction data is validated and entered immediately. With batch processing, the data is organised and stored before the master file is updated. Errors can occur during these steps.
Infrequent errors may occur in real-time processing; however, they are often tolerated. It is not practical to shut down the system for infrequent errors.
More computer operators are required in real-time processing, as the operations are not centralised. It is more difficult to maintain a real-time processing system than a batch processing system.
Pertanyaan
1. Jelaskan Transcation Processing system pada : rumah sakit, supermarket, lembaga kursus dan rental mobil
2. Jelaskan perbedaan antara batch processing dan real time processing?
B