Transaction Principles

Key Concepts of Transactions

A.C.I.D is an acronym that refers to the set of 4 key properties that define a transaction: Atomicity, Consistency, Isolation, and Durability. If a database operation has these A.C.I.D properties, it can be called an A.C.I.D transaction, and data storage systems that apply these operations are called transactional systems. A.C.I.D transactions guarantee that each read, write, or modification of a table has the following properties:

Atomicity

Atomicity guarantees that each transaction is treated as a single "atomic" unit. It either completes in its entirety or has no effect at all. This is essential for maintaining data integrity, as it prevents partial updates that could lead to inconsistent states.

Consistency

Consistency ensures that a transaction brings the database from one valid state to another. The database's rules, such as constraints, cascades, and triggers, are preserved.

Isolation

Isolation ensures that transactions are executed in isolation from one another. Concurrent transactions should not affect each other, providing a predictable outcome as if the transactions were executed sequentially.

Durability

Durability guarantees that once a transaction has been committed, it remains in the system even in the event of a system failure. This ensures the permanence of the transaction’s outcome.