Principles of Data storage

Question 1

What is a transaction on a database

Answer 1

Comprises of a series of small actions.

Question 2

What does a Database management system (DBMS) do

Answer 2

Ensures that all of the possible concurrent transactions will leave the date in the same state as if each transaction was performed one after another.

Question 3

What is record locking

Answer 3

Used to lock a record in a table until a transaction is completed. If the transaction fails, the record is unlocked for someone else to access.

Question 4

What are the four steps in ACID

Answer 4

Atomicity
Consistency
Isolation
Durability

Question 5

What does ACID do

Answer 5

Ensures all transactions complete successfully, or if they fail, the data is left as it was before.

Question 6

What is Atomicity in Acid

Answer 6

The classification of transactions as a single task that either passes or fails.

Question 7

What is Consistency in aCid

Answer 7

Ensures that the data being committed as part of the transaction compiles both with validation rules and referential integrity.

Question 8

What is Isolation in acId

Answer 8

Ensures that the data is locked whilst a transaction is processing.

Question 9

What is Durability in aciD

Answer 9

Ensures that once a transaction is completed, it is committed to the database and will stay in the database.