A transaction is an individual and indivisible set of operations that must either all succeed or fail as one unit.
Transaction Processing systems' examples include systems that manage sales order entry, airline reservations, payroll, employee records, manufacturing, and shipping.
Since most transaction processing today is interactive the term is often treated as synonymous with online transaction processing.
Jim Gray defined properties of a reliable transaction system in the late 1970s under the acronym ACID — atomicity, consistency, isolation, and durability.
Standard transaction-processing software, such as IBM's Information Management System, was first developed in the 1960s, and was often closely coupled to particular database management systems.