is the acronym for the four properties guaranteed
by transactions: atomicity, consistency, isolation,
Atomicity – means a transaction
must execute completely or not at all. This
means atomicity guaranteed that operations with
in a transaction undergo an all-or-nothing paradigm
– either all the database updates are performed
, or nothing happens is a n error occurs at
– is a transactional characteristic that must
be enforced by both the transactional system
and the application developer. Consistency guarantees
that a transaction leaves the system’s state
to be consistent after a transaction completes.
Consistency refers to the integrity of the underlying
data store. Atomicity helps enforce the system
always appears to be consistent.
– makes a transaction to execute without interference
from another process or transactions. Isolation
protects concurrently executing transactions
from seeing each others incomplete results.
Isolation allows multiple transactions to read
or write to a database without knowing about
each other because each transaction is isolated
from each others.
– means that all the data changes made during
the course of a transaction must be written
to some type of physical storage before the
transaction is successfully completed.