ACID properties in HLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to name the ACID property that ensures all parts of a transaction succeed or fail together.

HLD

The ACID property that guarantees all-or-nothing execution is called [1].

Drag options to blanks, or click blank then click option'

AAtomicity

BConsistency

CIsolation

DDurability

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing Atomicity with Consistency or Isolation.

Atomicity means the entire transaction happens completely or not at all.

2fill in blank

medium

Complete the code to identify the ACID property that ensures database rules are not broken after a transaction.

HLD

The ACID property that keeps data valid and follows rules is called [1].

Drag options to blanks, or click blank then click option'

AAtomicity

BConsistency

CIsolation

DDurability

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up Consistency with Atomicity or Durability.

Consistency ensures the database remains in a valid state after transactions.

3fill in blank

hard

Fix the error in naming the ACID property that controls how transactions appear isolated from each other.

HLD

The ACID property that ensures transactions do not interfere is called [1].

Drag options to blanks, or click blank then click option'

ADurability

BAtomicity

CConsistency

DIsolation

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing Isolation with Atomicity or Consistency.

Isolation means transactions run independently without affecting each other.

4fill in blank

hard

Fill both blanks to complete the description of the ACID property that guarantees data is saved permanently after a transaction.

HLD

The ACID property called [1] ensures data is [2] even after system failures.

Drag options to blanks, or click blank then click option'

ADurability

BAtomicity

Cpersisted

Disolated

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing Durability with Isolation or Atomicity.

Durability means once a transaction commits, its data is saved permanently.

5fill in blank

hard

Fill all three blanks to complete the sentence describing the ACID properties in order: Atomicity, Consistency, Isolation, Durability.

HLD

The ACID properties are [1], which means all-or-nothing; [2], which keeps data valid; [3], which prevents transaction interference.

Drag options to blanks, or click blank then click option'

AAtomicity

BConsistency

CIsolation

DDurability

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up the order or properties.

The first three ACID properties are Atomicity, Consistency, and Isolation, describing key transaction guarantees.

Practice

1. Which of the following ACID properties ensures that a transaction is completed fully or not at all, preventing partial updates?

easy

A. Atomicity

B. Consistency

C. Isolation

D. Durability

Solution

1. Step 1: Understand Atomicity in ACID

   Atomicity means a transaction is treated as a single unit. It either happens completely or not at all.

2. Step 2: Compare with other properties

   Consistency ensures data correctness, Isolation manages concurrent transactions, Durability guarantees data persistence after commit.

3. Final Answer:

   Atomicity -> Option A

4. Quick Check:

   Atomicity = All or nothing [OK]

Hint: Atomicity means all steps succeed or none do [OK]

Common Mistakes:

• Confusing Atomicity with Consistency
• Thinking Isolation means no partial updates
• Mixing Durability with Atomicity

2. Which ACID property is correctly described by this statement: Once a transaction commits, its changes are permanent even if the system crashes.

easy

A. Isolation

B. Atomicity

C. Durability

D. Consistency

Solution

1. Step 1: Identify property about permanence after commit

   Durability guarantees that once a transaction commits, changes survive crashes.

2. Step 2: Check other properties

   Isolation controls concurrent access, Atomicity ensures all-or-nothing, Consistency maintains valid data states.

3. Final Answer:

   Durability -> Option C

4. Quick Check:

   Durability = Permanent changes after commit [OK]

Hint: Durability means changes survive crashes [OK]

Common Mistakes:

• Mixing Durability with Atomicity
• Confusing Isolation with Durability
• Thinking Consistency means permanence

3. Consider two transactions T1 and T2 running concurrently. T1 reads a value, T2 updates it and commits. Which ACID property ensures T1 does not see T2's partial changes before commit?

medium

A. Isolation

B. Durability

C. Atomicity

D. Consistency

Solution

1. Step 1: Understand concurrent transaction behavior

   Isolation ensures transactions do not interfere and see only committed data.

2. Step 2: Relate to other properties

   Atomicity is about all-or-nothing, Durability about permanence, Consistency about valid data states.

3. Final Answer:

   Isolation -> Option A

4. Quick Check:

   Isolation = No dirty reads [OK]

Hint: Isolation prevents seeing uncommitted changes [OK]

Common Mistakes:

• Confusing Isolation with Atomicity
• Assuming Consistency controls concurrency
• Mixing Durability with Isolation

4. A developer notices that after a system crash, some committed transactions are lost. Which ACID property is most likely violated?

medium

A. Atomicity

B. Consistency

C. Isolation

D. Durability

Solution

1. Step 1: Identify property related to crash recovery

   Durability ensures committed transactions survive crashes.

2. Step 2: Analyze the problem

   Lost committed transactions after crash means Durability is violated.

3. Final Answer:

   Durability -> Option D

4. Quick Check:

   Durability = No data loss after crash [OK]

Hint: Lost commits after crash means Durability failure [OK]

Common Mistakes:

• Blaming Atomicity for crash data loss
• Confusing Isolation with crash recovery
• Assuming Consistency fixes crash issues

5. You design a banking system where multiple users transfer money concurrently. Which combination of ACID properties is most critical to prevent incorrect balances and lost updates?

hard

A. Consistency and Durability

B. Atomicity and Isolation

C. Isolation and Durability

D. Atomicity and Consistency

Solution

1. Step 1: Identify needs for concurrent money transfers

   Atomicity ensures each transfer completes fully or not at all, preventing partial money moves.

2. Step 2: Ensure no interference between concurrent transfers

   Isolation prevents transactions from seeing intermediate states, avoiding lost updates and incorrect balances.

3. Step 3: Evaluate other properties

   Consistency ensures valid data but depends on Atomicity and Isolation; Durability ensures persistence but not concurrency control.

4. Final Answer:

   Atomicity and Isolation -> Option B

5. Quick Check:

   Atomicity + Isolation = Safe concurrent transfers [OK]

Hint: Atomicity + Isolation prevent partial and conflicting updates [OK]

Common Mistakes:

• Ignoring Isolation leads to lost updates
• Assuming Consistency alone prevents concurrency issues
• Overlooking Atomicity causes partial transfers