Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A gaming company stores player profiles in Azure Cosmos DB using the NoSQL API. Each profile is a JSON document containing fields like playerId, userName, level, inventory (an array of items), and friends (an array of playerIds). The application frequently needs to query all players that have a specific item in their inventory (e.g., 'sword'). Which Cosmos DB feature should they use to support this query efficiently?
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
Change feed
Change feed is used to process changes to documents, not to query documents based on array content.
B
Distractor review
Stored procedures
Stored procedures allow server-side transactional logic but do not improve query performance for array containment queries.
C
Distractor review
Composite index
Composite indexes are designed for efficient ordering and filtering on multiple fields, not for array contains operations.
D
Best answer
Indexing policy with a wildcard index
A wildcard index ensures all paths (including arrays) are indexed, allowing efficient use of ARRAY_CONTAINS queries.
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: Indexing policy with a wildcard index — Cosmos DB automatically indexes every property by default, including array elements. However, to ensure optimal performance for queries using ARRAY_CONTAINS, you may need to define an indexing policy that includes the path to the inventory array. A wildcard index (e.g., /*) in the indexing policy ensures that all paths, including array elements, are indexed. Change feed is for capturing changes, not for querying. Stored procedures run server-side code but don't improve query performance. Composite indexes are for sorting or filtering on multiple properties, not specifically for array contains queries. Therefore, the best answer is 'Indexing policy with a wildcard index' as it makes sure the query uses an index.
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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