Atomocity, Consistency, Isolation, Durable

Transaction

A transaction is a sequence of sql Operations(commands), work as single atomic unit of work. This sequence of operations must satisfy 
4 properties, which is knwon as ACID test.

A(Atomicity):-The sequence of operations must be atomic, either all or no operations are performed.

C(Consistency):- When completed, the sequence of operations must leave data in consistent mode. All the defined 
relations/constraints must me Maintained.

I(Isolation): A Transaction must be isolated from all other transactions. A transaction sees the data defore the 
operations are performed , or after all the operations has performed, it can't see the data in between.

D(Durability): All operations must be permanently placed on the system. Even in the event of system failure, all the 
operations must be exhibit.