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

Question 1

What is transaction processing?

Answer 1

A transaction is a single logical operation on a database.

Question 2

What does ACID stand for?

Answer 2

Atomicity, Consistency, Isolation, Durability.

Question 3

Define Atomicity in ACID.

Answer 3

A transaction is all or nothing.

If one part fails, the whole transaction is rolled back.

Question 4

Define Consistency in ACID.

Answer 4

The database must remain in a valid state.

Question 5

Define Isolation in ACID.

Answer 5

Concurrent transactions don’t interfere with each other.

Question 6

Define Durability in ACID.

Answer 6

Once a transaction is committed, it is permanent.

Question 7

What is record locking?

Answer 7

A method to prevent simultaneous access to data, avoiding conflicts.

Question 8

What is data redundancy?

Answer 8

Duplication of data across the database, often avoided through normalisation.