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11 - Transaction processing and ACID

 1. A transaction can be defined as a group of tasks. A single task is the minimum processing unit which cannot be divided further.

  TRUE

  FALSE

 2. A transaction in a database system must maintain __________________ ? commonly known as ACID properties ? in order to ensure accuracy, completeness, and data integrity.

  Arduousness, Calibre, Isoluation and Drainabiity

  Atomicity, Consistency, Isolation, and Durability

  Amplication, Consistency, Identity and Durability

  Atomicity, Creativity, Isolation and Denegration

 3. In this state, the transaction is being executed. This is the initial state of every transaction.
Note: A transaction in a database can be in one of the following states (see diagram)
transaction_states.png

  Active

  Failed

  Partially committed

  Aborted

 4. If a transaction executes all its operations successfully, it is said to be committed. All its effects are now permanently established on the database system

  TRUE

  FALSE

 5. Read the excerpt below and decide what it is the definition of:
This property states that a transaction must be treated as an atomic unit, 
that is, either all of its operations are executed or none. There must be 
no state in a database where a transaction is left partially completed. 
States should be defined either before the execution of the transaction 
or after the execution/abortion/failure of the transaction.

  Durability

  Consistency

  Atomicity

  Isolation

 6. Read the excerpt below and decide what it is the definition of:
The database should be durable enough to hold all its latest updates
 even if the system fails or restarts. If a transaction updates a 
chunk of data in a database and commits, then the database will 
hold the modified data. If a transaction commits but the system 
fails before the data could be written on to the disk, then that 
data will be updated once the system springs back into action

  Isolation

  Durability

  Consistency

  Atomicity

 7. Read the excerpt below and decide what it is the definition of:
The database must remain in a consistent state after any transaction. 
No transaction should have any adverse effect on the data residing 
in the database. If the database was in a consistent state before 
the execution of a transaction, it must remain consistent after 
the execution of the transaction as well.

  Consistency

  Atomicity

  Isolation

  Durability

 8. Read the excerpt below and decide what it is the definition of:
In a database system where more than one transaction are being executed 
simultaneously and in parallel, the property of isolation states that
 all the transactions will be carried out and executed as if it is the 
only transaction in the system. No transaction will affect the existence 
of any other transaction

  Consistency

  Isolation

  Atomicity

  Durability

 9. A chronological execution sequence of a transaction is called a ______. A __________ can have many transactions in it, each comprising of a number of instructions/tasks.

   schedule

  serialisation

  module

  transaction record

 10. What is the following excerpt defining?
It is a schedule in which transactions are aligned in such a way 
that one transaction is executed first. When the first transaction
 completes its cycle, then the next transaction is executed. 
Transactions are ordered one after the other. This type of schedule
is called a serial schedule, as transactions are executed in a
 serial manner.

  First schedule

  Linear schedule

  Serial schedule

  Final schedule