The response time delay must be acceptable for the application to be considered real time ![]() ![]() E.g transferring money between accounts(the withdrawal must succeed for the transfer to succeed) if any steps fail no other should be completed large number of users simultaneously perform transactions(requests are also simultaneous)Ĭoncurrency: Two users cannot change the same data at the same timeĮ.g if an airline agent has reserved the last seat, another agent cannot tell another passenger that seat is availableĪtomicity: all steps involved in a transaction are completed successfully A network links terminals to mainframe computer Uses a terminal or workstation to enter data and display the results of the TPS Instant confirmation of a transaction but does require access to an online database Sorting the data is expensive and time consuming Used for pay cheques and when a time delay does not decrease the usefulness of the resultsĮrrors cannot be corrected during processing Collects the transaction data as a group and processes it later TPS systems reduce costs by reducing number of times data must be handled If roles and responsibilities are allocated, the TPS should maintain these requirements Must support an organisation's operations Flexibility results in too many opportunities for non standard operations, resulting in problems due to different transaction data Every transaction must be processed in the same way If failure occurs, recovery must be quick and accurate Turnaround time from transaction input to the production output must be a few seconds or less The four important characteristics include In the context of databases, a single logical operation on the data is called a transaction. ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties of database transactions. Main processes are collecting and storing Designed in conjunction with the organisation's procedures Examples: Point of Sale, credit card payments, Transaction is an event that generates or modifies data to be stored in an information system Transaction processing systems(TPS) collect, store, modify and retrieve the transactions
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