MongoDB interview questions part 37
MongoDB interview questions part 37
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Total Questions: 20
1. A rollback reverts _______ operations on a former primary when the member rejoins the replica set after a failover.
Correct Answer is : write
2. A priority __ member is a secondary that cannot become primary.
Correct Answer is : 0
3. Point out the correct statement :
Correct Answer is : Elections does not occur when the primary becomes unavailable and the replica set members autonomously select a new primary
4. A second data center hosts one priority 0 member that cannot become :
Correct Answer is : primary
5. A ______ member maintains a copy of the primary’s data set but is invisible to client applications.
Correct Answer is : hidden
6. _________ is used to read the contents of the rollback files.
Correct Answer is : bsondump
7. The db.________ method does not display hidden members.
Correct Answer is : isMaster()
8. In a sharded cluster, _______ do not interact with hidden members.
Correct Answer is : mongos
9. The order of documents returned by a query is not defined unless you specify a ______
Correct Answer is : sort()
10. Point out the correct statement :
Correct Answer is : Queries specify criteria, or conditions, that identify the documents that MongoDB returns to the clients
11. In aggregation pipeline, the _______ pipeline stage provides access to MongoDB queries.
Correct Answer is : $match
12. Which of the following method returns one document?
Correct Answer is : findOne()
13. Point out the wrong statement :
Correct Answer is : To scale the amount of data that MongoDB sends to applications, include a projection in the queries.
14. Which of the following is second argument to projection ?
Correct Answer is : find()
15. Which of the following query selects documents in the records collection that match the condition { “user_id”: { $lt: 42 } } ?
Correct Answer is : db.records.find( { “user_id”: { $lt: 42 } }, { “history”: 0 } )
16. Which of the following functionality is used for aggregation framework ?
Correct Answer is : $project
17. To suppress the _id field from the result set, specify _________ in the projection document.
Correct Answer is : _id: 0
18. Which of the following is not a projection operator ?
Correct Answer is : None of the mentioned
19. Which of the following flag can be set by mongo shell ?
Correct Answer is : noTimeout
20. Point out the correct statement :
Correct Answer is : The MongoDB server returns the query results in batches
