1. What is transaction?
Collections of operations that form a single logical unit of work are called transactions.
2. What are the two statements regarding transaction?
The two statements regarding transaction of the form:
3. What are the properties of transaction?
The properties of transactions are:
4. What is recovery management component?
Ensuring durability is the responsibility of a software component of the base system called the recovery management component.
5. 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.
6. What are the states of transaction?
The states of transaction are .
7. What is a shadow copy scheme?
It is simple, but efficient, scheme called the shadow copy schemes. It is based on 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.
8. Give the reasons for allowing concurrency?
The reasons for allowing concurrency is if the transactions run serially, a short transaction may have to wait for a preceding long transaction to complete, which can lead to unpredictable delays in running a transaction.
So concurrent execution reduces the unpredictable delays in running transactions.
9. What is average response time?
The average response time is that the average time for a transaction to be completed after it has been submitted.
10. What are the two types of serializability?
The two types of serializability is .
Conflict serializability
View serializability
11. Define lock?
Lock is the most common used to implement the requirement is to allow a transaction to access a data item only if it is currently holding a lock on that item.
12. What are the different modes of lock?
The modes of lock are: .
13. Define deadlock?
Neither of the transaction can ever proceed with its normal execution. This situation is called deadlock.
14. Define the phases of two phase locking protocol
. Growing phase: a transaction may obtain locks but not release any lock.
. Shrinking phase: a transaction may release locks but may not obtain any new locks.
15. Define upgrade and downgrade?
It provides a mechanism for conversion from shared lock to exclusive lock is known as upgrade.
It provides a mechanism for conversion from exclusive lock to shared lock is known as downgrade.
16. What is a database graph?
The partial ordering implies that the set D may now be viewed as a directed acyclic graph, called a database graph.
17. What are the two methods for dealing deadlock problem?
The two methods for dealing deadlock problem is deadlock detection and deadlock recovery.
18. What is a recovery scheme?
An integral part of a database system is a recovery scheme that can restore the database to the consistent state that existed before the failure.
19. What are the two types of errors?
The two types of errors are:
20. What are the storage types?
The storage types are:
Collections of operations that form a single logical unit of work are called transactions.
2. What are the two statements regarding transaction?
The two statements regarding transaction of the form:
- . Begin transaction
- . End transaction
3. What are the properties of transaction?
The properties of transactions are:
- Atomicity
- Consistency
- Isolation
- Durability
4. What is recovery management component?
Ensuring durability is the responsibility of a software component of the base system called the recovery management component.
5. 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.
6. What are the states of transaction?
The states of transaction are .
- Active .
- Partially committed
- Failed
- Aborted
- Committed
- Terminated
7. What is a shadow copy scheme?
It is simple, but efficient, scheme called the shadow copy schemes. It is based on 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.
8. Give the reasons for allowing concurrency?
The reasons for allowing concurrency is if the transactions run serially, a short transaction may have to wait for a preceding long transaction to complete, which can lead to unpredictable delays in running a transaction.
So concurrent execution reduces the unpredictable delays in running transactions.
9. What is average response time?
The average response time is that the average time for a transaction to be completed after it has been submitted.
10. What are the two types of serializability?
The two types of serializability is .
Conflict serializability
View serializability
11. Define lock?
Lock is the most common used to implement the requirement is to allow a transaction to access a data item only if it is currently holding a lock on that item.
12. What are the different modes of lock?
The modes of lock are: .
- Shared
- Exclusive
13. Define deadlock?
Neither of the transaction can ever proceed with its normal execution. This situation is called deadlock.
14. Define the phases of two phase locking protocol
. Growing phase: a transaction may obtain locks but not release any lock.
. Shrinking phase: a transaction may release locks but may not obtain any new locks.
15. Define upgrade and downgrade?
It provides a mechanism for conversion from shared lock to exclusive lock is known as upgrade.
It provides a mechanism for conversion from exclusive lock to shared lock is known as downgrade.
16. What is a database graph?
The partial ordering implies that the set D may now be viewed as a directed acyclic graph, called a database graph.
17. What are the two methods for dealing deadlock problem?
The two methods for dealing deadlock problem is deadlock detection and deadlock recovery.
18. What is a recovery scheme?
An integral part of a database system is a recovery scheme that can restore the database to the consistent state that existed before the failure.
19. What are the two types of errors?
The two types of errors are:
- Logical error
- System error
20. What are the storage types?
The storage types are:
- Volatile storage
- Nonvolatile storage
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