ACID Properties in Azure Data Fundamentals
Match each ACID property with its correct description. Properties: - Atomicity - Consistency - Isolation - Durability Descriptions: 1. Transactions appear to execute one after the other, even if they are concurrent. 2. Once a transaction is committed, the changes are permanently saved and survive failures. 3. A transaction either completes fully or is rolled back entirely. 4. A transaction brings the database from one valid state to another, obeying all rules. Which option correctly maps each property to its description?
Quick Answer
The correct mapping is Atomicity to 3, Consistency to 4, Isolation to 1, and Durability to 2. This is correct because each ACID property defines a specific guarantee for database transactions: Atomicity ensures a transaction is all-or-nothing, Consistency guarantees the database moves from one valid state to another while obeying all rules, Isolation makes concurrent transactions appear to execute one after the other, and Durability permanently saves committed changes so they survive failures. On the Microsoft Azure Data Fundamentals DP-900 exam, this matching question tests your foundational understanding of transactional integrity in Azure SQL Database and other relational systems. A common trap is confusing Consistency with Atomicity—remember that Atomicity is about the transaction’s completion, while Consistency is about the database’s state obeying rules. For a quick memory tip, think of the acronym A-C-I-D: All-or-nothing, Correct state, Isolated view, Data persists.
⚠ Common exam trap
It's easy for candidates to confuse the definitions of Consistency and Atomicity, often thinking Consistency means 'all-or-nothing' rather than 'valid state transitions,' or they swap Isolation with Durability by misremembering the 'permanent save' concept.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Atomicity → 3, Consistency → 4, Isolation → 1, Durability → 2
It accurately maps each ACID property to its definition. Atomicity ensures a transaction is all-or-nothing (3), Consistency guarantees the database moves from one valid state to another (4), Isolation makes concurrent transactions appear serial (1), and Durability ensures committed changes persist even after a failure (2). These are the standard definitions used in Azure SQL Database and other relational database systems.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Atomicity → 3, Consistency → 4, Isolation → 1, Durability → 2
Why this is correct
This is the correct mapping of ACID properties to their standard definitions.
- ✗
Atomicity → 4, Consistency → 3, Isolation → 2, Durability → 1
Why it's wrong here
This incorrectly swaps descriptions; Atomicity is not about validity, and Isolation is not about persistence.
- ✗
Atomicity → 2, Consistency → 1, Isolation → 3, Durability → 4
Why it's wrong here
This incorrectly assigns durability to a state validity description, and atomicity to a persistence description.
- ✗
Atomicity → 1, Consistency → 2, Isolation → 4, Durability → 3
Why it's wrong here
This incorrectly assigns atomicity to isolation, and durability to the all-or-nothing description.
Go deeper
Related to this question
Learn chapter
Relational Data Concepts
Key term
Azure SQL Database
Azure SQL Database is a fully managed relational database-as-a-service (DBaaS) in Microsoft Azure, based on the SQL Server engine, that handles scaling, backups, patching, and high availability automatically.
Key term
Relational database
A relational database organizes data into tables with rows and columns, where each table relates to others using unique keys, allowing efficient storage, retrieval, and manipulation of structured information.
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Same concept, more angles
3 more ways this is tested on DP-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. In a banking application, a transaction transfers $100 from Account A to Account B. The system deducts $100 from Account A successfully, but due to a network error, the credit to Account B fails. The application rolls back the deduction from Account A, ensuring that neither account is affected. Which ACID property is being enforced?
medium- ✓ A.Atomicity
- B.Consistency
- C.Isolation
- D.Durability
Why A: Atomicity ensures that a transaction is treated as a single, indivisible unit of work. In this scenario, the deduction from Account A and the credit to Account B must both succeed or both fail entirely. When the credit to Account B fails, the system rolls back the deduction from Account A, preserving the all-or-nothing nature of the transaction. This is the core behavior of atomicity in ACID-compliant database systems like Azure SQL Database or SQL Server.
Variation 2. A banking system processes a money transfer between two accounts. The system is designed so that after the transaction is committed, the results are permanently saved and survive any subsequent system failure, such as a power outage. Which ACID property ensures this behavior?
easy- ✓ A.Durability
- B.Atomicity
- C.Consistency
- D.Isolation
Why A: Durability ensures that once a transaction is committed, its changes are permanently stored and survive system failures, such as power outages or crashes. In this banking scenario, the money transfer results are written to non-volatile storage (e.g., disk) via a write-ahead log, guaranteeing that the committed state is recoverable even after a restart.
Variation 3. A company updates a customer's address in a database. The update must ensure that all existing orders still reference a valid customer ID. The database checks the foreign key constraint and rejects the update if it would violate referential integrity. Which ACID property does this enforcement represent?
medium- A.Atomicity
- ✓ B.Consistency
- C.Isolation
- D.Durability
Why B: Consistency ensures that any database transaction brings the database from one valid state to another, preserving all defined rules, including constraints like foreign keys. In this scenario, the foreign key constraint enforcement prevents an update that would leave orphaned order records, directly upholding the consistency property by rejecting the transaction if it violates referential integrity.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-900 exam.