1. What are the ACID properties?
APRIL/MAY-2011
(atomicity, consistency,
isolation, durability) is a set of properties that guarantee database
transactions are processed reliably.
In the context of databases, a single logical operation on the data is called a
transaction. For example, a transfer of funds from one bank account to another,
even though that might involve multiple changes (such as debiting one account
and crediting another), is a single transaction.
2. What are two pitfalls (problem)
of lock-based protocols? APRIL/MAY-2011
Ø Deadlock
Ø Starvation
3. What is transaction?
Collections of operations that form
a single logical unit of work are called transactions.
4. What are the two statements
regarding transaction?
The two statements regarding
transaction of the form:
Ø Begin transaction
Ø End transaction
5. What are the properties of
transaction?
The properties o f transactions are:
Ø Atomicity
Ø Consistency
Ø Isolation
Ø Durability
6. What is recovery management
component?
Ensuring durability is the
responsibility of a software component of the base system called the
recovery management component.
7. When is a transaction rolled
back?
Any changes that the aborted
transaction made to the database must be undone. Once the changes caused by an
aborted transaction have been undone, then the transaction has been rolled
back.
8. What are the states of
transaction?
The states of transaction are
Ø Active
Ø Partially committed
Ø Failed
Ø Aborted
Ø Committed
Ø Terminated
Ø
9. List out the statements
associated with a database transaction?
Ø Commit work
Ø Rollback work
10. What is a shadow copy scheme?
It is simple, but efficient, scheme
called the shadow copy schemes. It is based o n making copies of the database
called shadow copies that one transaction is active at a time. The scheme also
assumes that the database is simply
a file on disk.
uto;mso-margin-bottom-alt:auto;
line-height:normal'>Ø Consistency
Ø Isolation
Ø Durability
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