What are transaction-processing applications?

What are transaction-processing applications?
Answer: Transaction processing (TP) systems are designed to process user requests for information from a database, or requests to update a database. Technically, a database transaction is sequence of operations that is treated as a single unit (an atomic unit). All of the operations in a transaction have to be completed before the database changes are made permanent. This ensures that failure of operations within the transaction does not lead to inconsistencies in the database. An example of a transaction is a customer request to withdraw money from a bank account using an ATM.