For example, isolation relies on atomicity to roll back the enclosing transaction in the event of an isolation violation such as a deadlock consistency also relies on atomicity to roll back the enclosing transaction in the event of a consistency violation by an illegal transaction.Īs a result of this, a failure to detect a violation and roll back the enclosing transaction may cause an isolation or consistency failure. The same term is also used in the definition of First normal form in database systems, where it instead refers to the concept that the values for fields may not consist of multiple smaller value to be decomposed, such as a string into which multiple names, numbers, dates, or other types may be packed.Ītomicity does not behave completely orthogonally with regard to the other ACID properties of transactions. Performing these operations in an atomic transaction ensures that the database remains in a consistent state, that is, money is neither lost nor created if either of those two operations fails. It consists of two operations, withdrawing the money from account A and saving it to account B. At one moment in time, it has not yet happened, and at the next it has already occurred in whole (or nothing happened if the transaction was cancelled in progress).Īn example of an atomic transaction is a monetary transfer from bank account A to account B. As a consequence, the transaction cannot be observed to be in progress by another database client. A guarantee of atomicity prevents updates to the database occurring only partially, which can cause greater problems than rejecting the whole series outright. An atomic transaction is an indivisible and irreducible series of database operations such that either all occurs, or nothing occurs. In database systems, atomicity ( / ˌ æ t ə ˈ m ɪ s ə t i/ from Ancient Greek: ἄτομος, romanized: átomos, lit.'undividable') is one of the ACID ( Atomicity, Consistency, Isolation, Durability) transaction properties.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |