Transaction Processing (TP) services provide support for the on-line processing of information in discrete units called transactions, with assurance of the state of the information at the end of the transaction. This typically involves predetermined sequences of data entry, validation, display, and update or inquiry against a file or database. It also includes services to prioritize and track transactions. Transaction processing services may include support for distribution of transactions to a combination of local and remote processors.
A transaction is a complete unit of work. It may comprise many computational tasks, which may include user interface, data retrieval and communications. A typical transaction modifies shared resources. Transactions must also be able to be rolled back (that is, undone) if necessary, at any stage. When a transaction is completed without failure, it is committed. Completion of a transaction means either commitment or rollback.
Typically a transaction processing service will contain a transaction manager, which links data entry and display software with processing, database and other resources to form the complete service.
The sum of all the work done anywhere in the system in the course of a single transaction is called a global transaction. Transactions are not limited to a single application platform.
Copyright © The Open Group, 1998