4.6 Data Transaction

Question 1

Referential Integrity

Answer 1

The process of ensuring that data is consistent

Question 2

EDI

Answer 2

Computer to computer exchange of documents

Question 3

What sort of things does EDI manage?

Answer 3

Purchase Orders, invoices and shipping documents§

Question 4

Transaction

Answer 4

A single operation executed on data

Question 5

ACID

Answer 5

A set of properties to ensure that the integrity of the database is maintained under all circumstances

Question 6

Atomicity

Answer 6

Ensures transactions must be processed or cannot happen at all

Question 7

Consistency

Answer 7

A transaction must maintain the referential integrity rules between linked tables

Question 8

Isolation

Answer 8

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

Question 9

Durability

Answer 9

Once a transaction has been executed it will remain so regardless of circumstances surrounding it, such as in the event of a power cut

Question 10

Record Locking

Answer 10

The process of preventing simultaneous access to records in a database

Question 11

Benefits of record locking

Answer 11

To prevent inconsistencies or a loss of updates

Question 12

Serialisation

Answer 12

Ensures that transactions do not overlap in time and therefore cannot interfere with each other or lead to updates being lost

Question 13

Timestamp ordering

Answer 13

Every object in the database has a read timestamp, which is updated whenever an object is read or written

Question 14

Commitment ordering

Answer 14

Ensures no transactions are lost if two clients simultaneously try to update a record