Transaction processing, ACID (Atomicity, Consistency, Isolation, Durability), record locking and redundancy

Question 1

What is meant by referential integrity?

Answer 1

The process of ensuring consistency, this ensures that information
is not removed if it is required elsewhere in a linked database

Question 2

What is meant by a transaction?

Answer 2

A transaction is a single operation executed on data

Question 3

What is meant by transaction processing?

Answer 3

Transaction processing is when a series of actions is performed on one of these transactions

Question 4

What does ACID stand for?

Answer 4

• Atomicity
• Consistency
• Isolation
• Durability

Question 5

What is meant by atomicity?

Answer 5

A transaction must be processed in its entirety or not at all

Question 6

What is meant by consistency?

Answer 6

A transaction must maintain the referential integrity rules between linked tables

Question 7

What is meant by isolation?

Answer 7

Simultaneous executions of transactions should lead to the same result as if they were executed one after the other

Question 8

What is meant by durability?

Answer 8

Once a transaction has been executed it will remain so regardless of the
circumstances surrounding it

Question 9

What is meant by record locking?

Answer 9

• The process of preventing simultaneous access to records in a database, used in order to prevent inconsistencies or a loss of updates
• While one person is editing a record, this ‘locks’ the record so others cannot access the same record

Question 10

What is meant by redundancy?

Answer 10

• The process of having one or more copies of the data in physically different locations.
• This means that if there is any damage to one copy the others can be recovered