Students Learn About:
- real time transaction processing - the immediate processing of data
- the significance of data validation in transaction processing
- Types of transaction processing systems
- updating in on-line real time systems:
- – hardware requirements - large secondary storage
- – software requirements – on-line database and user friendly interface
- – steps in on-line real time processing
Useful Links:
What is Real Time Transaction Processing?
- RTTP is the immediate processing of data.
- Real time transaction processing systems complete transactions immediately they have been initiated.
- In most examples of real time transactions an online user initiates the transaction.
- Online users include employees of the organisation and also customers entering details via the web or other networks.
- Note that when a user directly interacts (participates) with the system they become a participant in the system.
- Provides instant confirmation yet requires access to online database.
- In real time or online systems, as opposed to batch systems, each transaction must complete within a reasonable amount of time.
- Involves using terminal or workstation to enter data and display results and a large number of users to simultaneously perform transactions.
- Uses computer network to link clients to servers, e.g. terminals link to mainframe computer and database.
- Every real-time TPS has a response time delay. For a TPS to be classified real-time the response time delay must be acceptable for that application.
- If an operation takes longer than a second or two then feedback must be provided to assure the user that processing is indeed taking place.
- Wait times of more than a few seconds are likely to be aborted by users in the belief that an error has occurred – this is particularly true of users who are not members of the organisation.
- This presents significant problems when transactions are initiated over the web. The organisation has no control over the speed of transmission once packets reach the Internet.
- However they do have control over the speed of data access and processing performed by their hardware and software.
- In general, real time transaction processing systems require faster direct (or random) access to secondary storage, faster and more secure communication links and more processing power than batch processing systems.
- Main disadvantage of RTTP is the hardware and software costs exceed batch
Real-time transaction processing is often called OLTP (online transaction processing). An online database is updated as the result of a business transaction.
Two main concerns:
- CONCURRENCY- ensures two users cannot change the same data at the same time. One must wait until the other is finished.
- ATOMICITY- ensures all the steps involved in a transaction are completed successfully as a group. If one step fails no other step should be completed.
Examples of RTTP systems include:
- RESERVATION SYSTEMS- involve setting aside a service or product for the customer to use at a future time.
- Commonly used for travelling such as in flight or train bookings and motel reservations.
- Require an acceptable response time because transactions are made in presence of customers.
- POS TERMINALS- are used by retail stores to sell goods and services.
- Send inventory data to a central computer (mainframe or midrange) when sale is made which does the processing for entire chain.
- To accomplish this the data is converted to a form that is easily transmitted through a communication system.
- If the POS terminal immediately processes the transaction it minimises the cost of batch handling.
- Advantage is that the correct price of the product is received once the product is entered usually through barcodes when barcode readers are used to identify the product.
- The POS terminal can provide price and any other relevant information about the product.
- LIBRARY LOAN SYSTEM- is used to keep track of items borrowed from the library.
- When a book is borrowed the librarian scans the barcode on the person’s membership card and the book.
- This information and the date are immediately recorded on the library database.
- Similar to reservation system as operational activities involve keeping information on products, availability, usage and maintenance.
- Also has ‘front office’ and ‘back office’.
- Only difference is that loan system has more items, which are stored in a data warehouse.
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.
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