Adam works as a Database Designer for DataOne Inc. The company has a SQL Server database. Adam has
to ensure that either all the databases are updatedor none of them are updated, so that the databasesremain
synchronized. Which of the following will he use toaccomplish the task?
A.
Native auditing
B.
Two-phase commit
C.
Encryption
D.
Concurrency control
Explanation:
A two-phase commit is a feature of transaction processing systems, enabling databases to be returned to the
pre-transaction state if some
error condition occurs. A single transaction can update many different databases. A two-phase commit strategy
is designed to ensure that
either all the databases are updated or none of them, so that the databases remain synchronized. Answer C is
incorrect. Encryption provides an additional security layer, protecting the data from unauthorized viewing with
the help of
an algorithm called cipher. Even if access to the database is obtained, it will not be easy to decipher encrypted
data into a readable form.
Answer A is incorrect. Native auditing is the process of extracting trails on a regular basis so that they can be
transferred to a designated security system where the database administrators do not have access. This
ensures a certain level of segregation of duties and provides evidence that the native audit trails were not
modified by authenticated administrators. Answer D is incorrect. Concurrency control in database management
systems ensures that database transactions are performed concurrently without the concurrency violating the
data integrity of a database. Executed transactionsshould follow the ACID rules. This mechanism is required
to manage multiple users accessing the same groups of resources with the least possible overhead, either
optimized for a specific task, or general purpose.