Database Transaction

What is a Database Transaction?

A database transaction is a unit of work performed within a database management system against a database and treated coherently and reliably independent of other transactions. A transaction can be any change in a database. Transactions in a database have two main purposes:

1. To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure, when execution stops and many operations upon a database remain uncompleted, with unclear status.

2. To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the programs' outcomes are possibly erroneous.

In a database management system, a transaction is a single unit of logic or work, sometimes made up of multiple operations. Any logical calculation done in a consistent model in a database is known as a transaction.

Types and Examples

One example is a transfer from one bank account to another: the complete transaction requires subtracting the amount to be transferred from one account and adding that same amount to the other.