10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The MongoDB-DBA exam has 75 questions and runs 1 hour 30 minutes.
These 10 free MongoDB-DBA questions are organized by exam domain, so you can see how each part of the MongoDB Associate Database Administrator blueprint is tested. Reveal the answer and explanation under each question.
A ticket document contains tags: ["urgent", "billing"]. A DBA runs db.tickets.updateOne({ _id: 1 }, { $addToSet: { tags: "urgent" } }). What is the result?
Correct answer: C - matchedCount: 1, modifiedCount: 0 - the array is left unchanged
Documents in the sensors collection contain a readings array. A DBA must return only documents in which a SINGLE array element is both greater than 20 and less than 30. Which query is correct?
Correct answer: D - { readings: { $elemMatch: { $gt: 20, $lt: 30 } } }
A DBA runs db.orders.find({ status: "shipped" }).explain("executionStats") and the output shows stage: "COLLSCAN", nReturned: 14, totalDocsExamined: 4200000. What is the MOST appropriate first action?
Correct answer: A - Create an index on the status field
Queries against the events collection match type with an equality condition, filter timestamp with a range condition, and sort the results by severity. Following the ESR guideline, which compound index is BEST?
Correct answer: C - { type: 1, severity: 1, timestamp: 1 }
An explain("executionStats") result shows an IXSCAN stage with no FETCH stage, and totalDocsExamined: 0. What does this indicate?
Correct answer: C - The query was satisfied entirely from the index
A three-member replica set must be upgraded to a newer MongoDB release with minimal disruption. What is the correct order of operations?
Correct answer: B - Upgrade each secondary in turn, then step down and upgrade the primary
A DBA needs to identify which collection is consuming the most read and write time on a busy mongod. Which tool reports this directly?
Correct answer: D - mongotop
A junior DBA must be able to create indexes and view collection statistics on the reporting database, but must NOT be able to read document data. Which built-in role should be granted?
Correct answer: B - dbAdmin
An application user was created on the admin database and granted readWrite on sales. The application connects with mongodb://appuser:***@host:27017/sales and fails authentication, yet the same credentials succeed in mongosh when --authenticationDatabase admin is supplied. Which connection string option resolves this?
Correct answer: A - authSource=admin
A replica set is deployed as one primary, one secondary, and one arbiter. The secondary is taken offline for maintenance. What happens to writes issued with w: "majority"?
Correct answer: B - They block until the write concern times out or the secondary returns
The MongoDB-DBA exam also covers these domains. Drill them in the full free practice test:
The full bank has 1,020 more MongoDB-DBA questions with explanations.
Continue in the free practice test →
View plans