Classical relation database follow the ACID Rule
A database transaction, must be atomic, consistent, isolated and durable. Below we have discussed these four points.
Atomic : A transaction is a logical unit of work which must be either completed with all of its data modifications, or none of them is performed.
Consistent : At the end of the transaction, all data must be left in a consistent state.
Isolated : Modifications of data performed by a transaction must be independent of another transaction. Unless this happens, the outcome of a transaction may be erroneous.
Durable : When the transaction is completed, effects of the modifications performed by the transaction must be permanent in the system.