The answer is CustomerKey. This is the most appropriate distribution column for a hash-distributed table in Azure Synapse because it has high cardinality—meaning many unique values—which ensures data is evenly spread across distributions and avoids data skew, and it is frequently used in joins with dimension tables, a key requirement for hash distribution column selection in Azure Synapse. On the Microsoft Azure Data Fundamentals DP-900 exam, this concept tests your understanding of how to optimize query performance by choosing a column that balances data and supports common join patterns; a common trap is selecting a low-cardinality column like DateKey, which would cause uneven distribution and slow queries. Memory tip: think “High-cardinality join key” to remember that the best distribution column is both unique and used in joins.
DP-900 Describe core data concepts Practice Question
This DP-900 practice question tests your understanding of describe core data concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Refer to the exhibit. You are designing a fact table for a data warehouse. The table will store sales transactions with daily granularity. Which column would be most appropriate as the distribution column in a hash-distributed table in Azure Synapse Analytics?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
CustomerKey
CustomerKey (B) is the most appropriate distribution column because it has high cardinality and is frequently used in joins with dimension tables, ensuring data is evenly distributed across distributions in Azure Synapse Analytics. A hash-distributed table requires a column with many unique values to avoid data skew, and CustomerKey is a natural key for sales transactions that meets this requirement.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
SalesAmount
Why it's wrong here
SalesAmount is a measure, not a dimension key; not suitable for distribution.
✓
CustomerKey
Why this is correct
CustomerKey has high cardinality and is frequently used in joins, making it a good distribution column.
Related concept
Read the scenario before looking for a memorised answer.
✗
ProductKey
Why it's wrong here
ProductKey may also be good, but CustomerKey is typically a better choice for even distribution.
✗
OrderDate
Why it's wrong here
OrderDate has low cardinality (e.g., daily dates) and can cause data skew.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Microsoft often tests the misconception that any column with high cardinality is suitable for hash distribution, but the trap here is that the column must also be frequently used in joins and evenly distribute data, not just have many unique values.
Detailed technical explanation
How to think about this question
In Azure Synapse Analytics, hash distribution uses a hash function on the distribution column to assign rows to one of 60 distributions. The choice of distribution column directly impacts query performance: if the column has low cardinality or is not used in joins, data can become skewed, causing some distributions to handle far more data than others. For fact tables with daily granularity, CustomerKey is ideal because it balances data evenly and aligns with star-schema join patterns, whereas OrderDate would cause all rows for a single day to land on the same distribution, creating a bottleneck.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this DP-900 question in full detail.
Describe core data concepts — This question tests Describe core data concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: CustomerKey — CustomerKey (B) is the most appropriate distribution column because it has high cardinality and is frequently used in joins with dimension tables, ensuring data is evenly distributed across distributions in Azure Synapse Analytics. A hash-distributed table requires a column with many unique values to avoid data skew, and CustomerKey is a natural key for sales transactions that meets this requirement.
What should I do if I get this DP-900 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.