Software Architect's Handbook

Database transactions

A database transaction is a sequence of operations that are performed as a single unit of work. They play an important role in maintaining data integrity and consistency even when data is being accessed and changed at the same time. They provide units of work that either complete in their entirety or will not be committed at all.

Transactions can recover from failures and keep the database in a consistent state. Transactions also provide isolation so that a record that is in the process of being modified by one transaction is not affected by a concurrent transaction that must update the same record. Transactions, once they are complete, are written to durable storage.