The word ACID expresses the role of the transaction in the mission-critical application. ACID is created by the transaction pioneer, represents inertability, consistency, isolation, and persistence.
These attributes ensure the security of presence, strengthening the role of transactions as a "full or no" proposition, and this proposition is designed to reduce management loads when there are many variables.
Unmetibility
A series of operations occurs between a work unit where the application's begin transaction and end transaction statements. The transaction is only executed once, and it is not enough, that is, complete all work or do not do anything.
The operation associated with a transaction usually has a common goal and is interdependent. If the system only performs one subset of these operations, the overall goal of the transaction may be destroyed. The non-variability eliminates the possibility of system processing operation subset.
consistency
The transaction is a complete unit because it maintains the consistency of the data, and the data is consistently converted from one data to another.
Consistency requires data that retains transaction binding in semantics. Some responsibilities of certain maintenance consistency are borne by the application developers, and they must ensure that the application has enforced all known integrity constraints. For example, when developing an application for transfer, avoid moving the decimal point during the transfer process.
Isolation
The transaction is an isolation unit that allows each parallel executive transaction performance like a unique transaction running in the system.
Isolability requirements Even if there may be other transactions that are running, each transaction is like a unique transaction in the operational data store. The transaction should never look at the intermediate stage of other transactions.
The highest isolation level will be obtained when the transaction can be serialized. At this level, the results obtained from a set of parallel executable transactions are the same as those obtained by continuously run each transaction. Since height isolation limits the number of transactions that can be performed in parallel, some applications reduce the isolation level to exchange greater throughput.
Persistent
The transaction is also a recovery unit. If the transaction is successful, the system will still guarantee the transaction even if the computer crashes immediately after the submission is submitted. The dedicated record allows the system to restart the process to complete the unfinished operation so that the transaction is sustainable.
