Affairs
A transaction is a series of strict application of the operation, all operations must be completed successfully, otherwise made in each operation, all changes are undone. That is, the transaction has atomicity, a series of operations in a transaction either all succeed, or none do.
ACID Description :
Atomicity (Atomicity), consistency (Correspondence), isolation (Isolation), persistent (Durability).
(1) Atomicity: All operations of the entire transaction, either completed or not completed all impossible stuck in the middle of a link. Transaction error occurs during execution, it will be rolled back (Rollback) to the state before the start of the transaction, as the transaction never performed the same.
(2) Consistency: before the transaction begins and after the end of the transaction, integrity constraints of the database is not corrupted.
(3) Isolation: isolation transaction execution, so that if they were the only operating system executing within a given time. If there are two transactions running at the same time, perform the same function, isolation transaction will ensure that each transaction in the system that only the transaction using the system. This property is sometimes referred to as serialization, in order to prevent confusion between the transaction operations, or be serialized serialized request, so that only one request at the same time for the same data.
(4) Persistence: After the transaction is completed, the firm changes made to the database will be stored in the persistent database, and will not be rolled back.