Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A travel booking application stores user itineraries in Azure Cosmos DB using the NoSQL API. Each itinerary document contains: UserID (unique to user), ItineraryID, Destination, BookingDate, and a nested array of Activities. The most common query is: 'Retrieve all itineraries for a specific UserID sorted by BookingDate descending.' To minimize Request Unit (RU) consumption, which partition key should be chosen?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
ItineraryID
Using ItineraryID would scatter each itinerary across partitions. A query for a user's itineraries would need to touch many partitions, increasing RU consumption.
B
Best answer
UserID
UserID is the most common filter. All documents for one user are stored on the same partition, making the query single-partition and highly efficient.
C
Distractor review
Destination
Destination may lead to unbalanced partition sizes (e.g., 'Paris' having many documents) and queries by UserID would still be cross-partition if the user has multiple destinations.
D
Distractor review
BookingDate
BookingDate would likely cause hot partitions (e.g., today's date) and queries for a specific UserID would span multiple partitions, increasing RU.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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FAQ
Questions learners often ask
What does this DP-900 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: UserID — Choosing UserID as the partition key ensures that all itineraries for a given user reside on the same logical partition. The query then targets a single partition, avoiding expensive cross-partition queries. ItineraryID would distribute data too granularly, leading to fan-out on nearly every query. Destination might cause hot partitions if only a few destinations are popular, and BookingDate would not align well with the UserID filter, again causing cross-partition queries.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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