MongoDB Certified DBA Associate Exam (Based on MongoDB 4.4) (C100DBA) Free Practice Test

Question 1

Which of the following are valid json documents? Select all that apply.

A. {"a":l, "b":{"b":l, "c":"foo", "d":"bar", "e":[l,2,4]}}

B. {"name":"Fred Flintstone";"occupation":"Miner";"wife":"Wilma"}

C. { }

D. {"city":"New York", "population", 7999034, boros:{"queens", "manhattan", "staten island", "the bronx", u "brooklyn"}}

Correct Answer: A,C

Question 2

The oplog (operations log) is a special capped collection that keeps a rolling record of all operations that modify the data stored in your databases. All the replica set members contain a copy of the oplog in the following collection:

A. <database>..oplog.rs

B. <replicasetid>.oplog.rs

C. local.oplog.rs

D. oplog.rs

Correct Answer: C

Question 3

Consider that you have a collection called population which has fields state and city. Which of the following query will calculate the population grouped by state and city?

A. db.population.aggregate( [{ $group: { _id: { state: "$state", city; "$city" },pop: { $sum: 1 > > >] )

B. db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB

C. db.population.aggregate( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $pop: 1 } } }] )

D. db.population.aggregate( [{ $group: { _id: { state: Estate", city: n$city" },pop: { $sum: "$pop" } } }] )

Correct Answer: D

Question 4

What tool would you use if you want to save a gif file in mongo?

Correct Answer:

mongofile

Question 5

What tool do you use if you want to extract a CSV from mongo?

Correct Answer:

mongoexport

Question 6

Aggregation Pipelines have a limit of:

A. 2 MB document and no limit on RAM

B. 16 MB document and 100 MB RAM

C. No limit on document and 100 MB RAM

D. 2 MB document and 100 MB RAM

Correct Answer: B

Question 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. $group

B. $aggregate

C. $project

D. $match

Correct Answer: C

Question 8

Which of the following is correct about MongoDB?

A. MongoDB supports some of the SQL functions

B. MongoDB supports geospatial indexes

C. MongoDB uses JSON format to represent documents

D. MongoDB supports collection joins

Correct Answer: B

Question 9

Which of the following commands finds all the documents in the posts collection with post timestamp field as null?

A. db.posts.find( { post_timestamp: { $fieldtype: 10 } } )

B. db.posts.find( { post_timestamp: { $type: null } } )

C. db.posts.find( { post_timestamp : { $type; 10 > > )

D. db.posts.find( { post_timestamp: { $fieldtype: null } } )

Correct Answer: B

Question 10

Write the command(s) are correct to enable sharding on a database "testdb" and shard a collection "testCollection" with _id as shard key.

Correct Answer:

sh.enableSharding("testdb") & sh.shardCollection("testdb.testCollection", {_id : 1 }, true )

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MongoDB Certified DBA Associate Exam (Based on MongoDB 4.4) (C100DBA) Free Practice Test