C100DBA問題集、MongoDB実際の試験問題

質問 1

Consider that the posts collection contains an array called ratings which contains ratings given to the post by various users in the following format:

Which of the following query will return all the documents where the ratings array contains elements that in some combination satisfy the query conditions?

A. db.inventory.find( { ratings: { ratings.$: { $gt: 5, $lt: 9 } } } )

B. db.inventory.find( { ratings: { $elemMatch: { $gte: 3, $lte: 6 } } } )

C. db.inventory.find( { ratings: { $elemMatch: { $gt: 3, $lt: 6 }

D. db.inventory.find( { ratings: { ratings: { $gt: 5, $lt: 9 } } } )

正解: D

質問 2

You have designed a web application with mongoDB. You have configured replication. The replica set is in place and function properly. What happens in case of failure?

A. Failover happens automatically

B. Failover needs to be done manually

C. Switchover needs to be done manually

D. Switchover happens automatically

正解: A

質問 3

Which of the following index would be optimum for the query?
Select all valid. db.test.find( { a : 5, c : 2 })

A. db.test.ensurelndex( { c:l, a: 1})

B. CH db.test.ensurelndex( { a :1, c:l})

C. db.test.ensurelndex( { a : 1, c: 1, d: 1, b : 1})

D. db.test.ensurelndex( { a: 1, b :1, c:l, d:l})

正解: B,C

質問 4

Which operations add new documents to a collection?

A. delete

B. Create

C. insert

D. update

正解: B,C

質問 5

What is the maximum size of a MongoDB document?

A. There is no maximum size. It depends on the RAM.

B. 12 MB

C. 16 MB

D. 2 MB

正解: C

質問 6

Below is a sample document in a given collection test.
{ a : 5, b : 3, c: 2, d : 1 }
Given a compound index { a: 1, b:l, c:l, d:l}, Which of the below query will not use in-memory sorting? Select all valid.

A. db.test.find( { a: 5, b: 3 } ).sort( { c: 1, d : 1 } )

B. db.test.find( { a: 5, b: 3 } ).sort( { a: 1, b: 1, c: 1 } )

C. db.test.find( { a: 5, b: 3 } ).sort( { a: 1} )

D. db.test.find( { a: 5, b: 3 } ).sort( {c: 1 } )

正解: A,D

質問 7

The following aggregation option is used to specify the specific fields that needs to be passed to the next stage of the aggregation pipeline:

A. $project

B. $aggregate

C. $group

D. $match

正解: A

MongoDB Certified DBA Associate Exam (Based on MongoDB 4.4) - C100DBA 模擬練習