ACID properties in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the 'A' in ACID stand for?

The 'A' stands for Atomicity. It means a transaction is all or nothing: either all steps complete successfully, or none do.

beginner

Explain Consistency in ACID properties.

Consistency ensures that a transaction brings the database from one valid state to another, following all rules and constraints.

intermediate

What does Isolation mean in the context of ACID?

Isolation means transactions run independently without interfering with each other, as if they were executed one after another.

beginner

Describe Durability in ACID properties.

Durability guarantees that once a transaction is committed, its changes are permanent, even if the system crashes afterward.

intermediate

Why are ACID properties important in database systems?

ACID properties ensure reliable, predictable, and safe transactions, preventing data corruption and maintaining integrity.

Which ACID property ensures that a transaction is fully completed or not done at all?

A Atomicity

B Consistency

C Isolation

D Durability

Atomicity means the transaction is all or nothing.

Which property guarantees that committed data will not be lost after a crash?

A Isolation

B Consistency

C Durability

D Atomicity

Durability ensures data persists after commit, even if the system fails.

What does Isolation prevent in concurrent transactions?

A Interference between transactions

B Partial updates

C Data loss

D Invalid data states

Isolation prevents transactions from interfering with each other.

Consistency in ACID means:

A Transactions are isolated

B Database rules are always followed

C Changes are permanent

D Transactions are atomic

Consistency ensures database rules and constraints are maintained.

Which ACID property is about the database moving from one valid state to another?

A Atomicity

B Isolation

C Durability

D Consistency

Consistency ensures valid states before and after transactions.

Explain each ACID property with a simple real-life example.

Think about actions like buying something online or transferring money.

Why is it important for a database to follow ACID properties? Describe the risks if they are not followed.

Consider what happens if transactions fail halfway or data gets mixed up.