20+ practice questions focused on CRUD Operations — one of the most tested topics on the MongoDB Certified DBA Associate exam. Each question includes a detailed explanation so you learn why the right answer is correct.
Start CRUD Operations PracticeAn application needs to update a user document by incrementing the 'login_count' field by 1 only if the 'status' field is set to 'active'. Which method is most efficient for this atomic operation?
Explanation: The updateOne method with an $inc operator and a query filter is the standard approach for atomic updates in MongoDB. By specifying the condition in the query filter, MongoDB ensures the operation only executes when the status is active, avoiding race conditions that could occur if the application fetched the document, modified it locally, and sent it back. This promotes data integrity and reduces network round trips.
Which TWO of the following statements regarding the 'upsert' option in MongoDB update operations are correct?
Explanation: The upsert option is a powerful feature that combines update and insert logic into a single atomic operation. When set to true, MongoDB will update the document if it matches the filter, or create a new document if no matches are found. This is critical for idempotency in application logic, reducing the need for explicit existance checks before performing updates, which simplifies code paths and prevents race conditions.
Which THREE of the following are valid ways to modify an array field in a document?
Explanation: Modifying arrays is a common task in MongoDB. Operators like $push, $addToSet, and $pull provide specific logic for adding or removing items. $push allows duplicates, $addToSet ensures uniqueness, and $pull removes elements. Mastering these operators is essential for handling nested data structures and managing user-generated content or tagging systems effectively within a document-oriented database schema.
Refer to the exhibit. What will be the result of this query?
Explanation: The query returns all documents where the status field is 'active'. The projection { name: 1, _id: 0 } explicitly includes the 'name' field and explicitly excludes the '_id' field, which is included by default. This is a common pattern for generating clean reports or API responses where internal database identifiers should be hidden from the client or where unnecessary data transfer is undesirable for application performance.
Which THREE of these are valid methods for deleting documents from a MongoDB collection?
Explanation: MongoDB provides specific methods to handle document removal. deleteOne() and deleteMany() are the standard, modern approaches for filtering and removing data. drop() is a collection-level operation that removes all documents and indexes simultaneously. Knowing the difference between these is crucial for data management, as dropping a collection is an irreversible action that bypasses individual document deletion criteria and significantly alters the collection's structure.
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Practice all CRUD Operations questions1. Baseline your knowledge
Start with 10 questions to gauge your current understanding of CRUD Operations. This tells you whether you need a concept refresher or just practice.
2. Review every explanation
For each question — right or wrong — read the full explanation. Understanding why an answer is correct is more valuable than knowing the answer itself.
3. Focus on exam traps
CRUD Operations questions on the C100DBA frequently use trap wording. Look for subtle differences in answers that test your precision, not just general knowledge.
4. Reach 80% consistently
Do repeated sessions until you score 80%+ three times in a row. Then move to mixed-mode practice to test cross-topic recall under realistic conditions.
The exact number varies per candidate. CRUD Operations is tested as part of the MongoDB Certified DBA Associate blueprint. Practicing with targeted CRUD Operations questions ensures you can handle any format or difficulty that appears.
Yes. Courseiva provides free C100DBA practice questions across all exam topics and domains. The platform includes topic-based practice, mock exams, missed-question review, bookmarked questions, and readiness tracking — no account required.
Difficulty is subjective, but CRUD Operations is a high-priority exam concept tested in multiple ways — direct recall, scenario analysis, and command-output interpretation. Consistent practice is the best way to build confidence.
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