Which of the following properties of the database transaction has been defined in the given
statement: “Either all the changes or no changes have been made in the database.”
A.
Durability
B.
Atomicity
C.
Consistency
D.
Isolation
Explanation:
Atomicity ensures that a transaction is either committed (i.e., all the changes made to the database
are permanently saved) or rolled back (i.e., no changes have been made, and the database is
recovered to its original state).
Answer D is incorrect. The isolation property ensures that a
transaction is isolated from any outside operation. This means that data in a transaction cannot be
viewed in its intermediate state.
Answer A is incorrect. The durability property ensures that once the user has been notified about
the success of the transaction, the transaction will continue and will not revert. This implies that the
transaction has been checked for all data integrity constraints, and no constraint has been found
violated.
Answer C is incorrect. The consistency property ensures that the database remains in a
valid state before and after the transaction is committed. This means that a transaction cannot
violate business rules, or integrity constraints, of the database. For example, if an integrity constraint
states that an account cannot be debited if the balance is less than $500, then any transaction
violating this rule will be aborted.