C100DBA MongoDB Certified DBA Associate Exam Questions

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MongoDB Certified DBA Associate C100DBA exam questions are online, which are good material for you to take the test. There are 60 multiple choice questions in real MongoDB C100DBA exam, and you have 90 minutes to complete all the questions. The exam cost is $150. We provide online MongoDB certification C100DBA exam questions for you to take. Free MongoDB C100DBA exam questions are available below.

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1. Which of the following collections stores authentication credentials in MongoDB?

test.users

local.users

system.users

users.users

2. You have the following index on the toys collection:

{

"manufacturer" : 1,

"name" : 1,

"date" : -1

}

Which of the following is able to use the index for the query? Check all that apply.

db.toys.find( { name : "Big Rig Truck", date : "2013-02-01", manufacturer : "Tanko"

db.toys.find( { manufacturer : "Matteo", name : "Barbara", date : "2014-07-02" } )

db.toys.find( { date : "2015-03-01", manufacturer : "Loggo", name : "Brick Set" } )

3. What is the on-premise solution having functionality equivalent to cloud manager?

Service Manager

Replica Manager

Ops Manager

Journaling

4. In a sharded replica set environment, the w Option provides ability for write concern and j Option provides ability for the data to be written on disk journal. Consider that we have a seven member replica set and we want to assure that the writes are committed to journal.

What should be the value of j?

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

$project

$aggregate

$match

$group

6. CORRECT TEXT

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

7. Which command can be used to rebuild the indexes on a collection in MongoDB?

db.collection.createlndex({relndex:l})

db.collection.reIndex({author:l})

db.collection.relndexQ

db.collection.createIndex({author:l}).reIndex()

8. What is the first task that a secondary would perform on being prompted by another secondary for an election?

Start the election process for primary

Vote for the first secondary so that it would become the next primary

Vote for itself and then call for election

Connect to primary to confirm its availability

9. What does the following $slice query return using the following command? db.posts.find( {}, { comments: { $slice: [ -10, 5 ] } } )

Returns 5 comments, beginning with the last 10 items

Returns 10 comments, beginning with the last

Returns 10 comments, beginning with the first

Returns 5 comments, beginning with the first 10 items

10. Which of the following is supported by MongoDB?

Transaction Management

ACID Transactions

Journaling

Relationships between Collections (Primary Key Foreign Key)

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11. Which mongodb tool is used to report details on number of database operations in MongoDB?

mongostat

mongotop

mongorestore

mongodump

12. As per the aggregation pipeline optimization concepts, if you have a $sort followed by a $match:

Providing these parameters in any order does not impact the performance

$sort moves before $match

MongoDB does not do any movements by default and will use the order provided

$match moves before $sort

13. Which is the correct order (lowest to highest) in which MongoDB compares the BSON types?

Number, Null, String and Object

Null, Number, Object and String

Null, Number, String and Object

String, Null, Number and Object

14. In a replicated cluster, which of the following node would only be used during an election?

arbiter

primary

hidden

secondary

15. What does the totalKeysExamined field returned by the explain method indicate?

Number of documents that match the query condition

Number of index entries scanned

Details the completed execution of the winning plan as a tree of stages

Number of documents scanned

16. Consider the following posts document:

Which of the following queries will return the documents but with only the first two tags in the tags array?

db.posts.find({author:"Tom"».limit({tags:2})

db.posts.find({author:"Tom"».limit($slice:{tags:2>)

Both "db.posts.find({author:"Tom"},{tags:{$slice:2}})" and "db.posts.find({author:"Tom"}).limit($slice: {tags:2})" are valid. $slice works both with projection and limit.

db.posts.find({author:"Tom">,{tags:{$slice:2»)

17. In a sharded replica set environment, the w Option provides ability for write concern and j Option provides ability for the data to be written on disk journal. Consider that we have a seven member replica set and we want to assure that the writes are committed to journal.

What should be the value of j?

18. Given a collection posts as shown below having a document array comments, which of the following command will create an index on the comment author descending?

db.posts.createIndex({^comments.$.author":-l});

db. posts.createIndex({^comments.author" :1});

db.posts.createIndex({^commerits.author";-!});

19. In a sharded replicas set environment with multiple mongos servers, which of the following would decide the mongos failover?

mongos

mongo shell

individual language drivers

mongod

20. Mongodb does provide high availability via which option?

Replication

Indexing

Sharding

Journaling

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21. What does the output x of the following MongoDB aggregation query result into; db.posts.aggregate( [ { $group: { _id; "$author", x: { $sum: $likes } } } ] )

Average of likes on all the posts of an author, grouped by author

Number of posts by an author

Sum of likes on all the posts by all the authors

Sum of likes on all the posts by an author, grouped by author

22. What read preference should your application use if you want to read from the primary under normal circumstances but allow reads from secondaries when a primary is unavailable?

secondaryPreferred

Secondary

nearest

primary

primaryPreferred

23. What is the use of mongodump and mongorestore tools?

backup mongodb deployment

audit mongodb deployment

performance tune mongodb deployment

replicate mongodb deployments

24. Which of the following needs to be performed prior to initiate backup on a sharded cluster?

db.stopBalancer( )

sh.stopServer( )

db.stopServer( )

sh.stopBalancer( )

25. What is the maximum size of Index Key Limit and Number of Indexes per collection?

1024 bytes and 64 indexes

12 mega bytes and 64 indexes

64 bytes and 1024 indexes

1024 bytes and unlimited indexes

26. To add a new user and enable authentication in MongoDB, which of the following steps

need be executed?

update users collection and restart mongodb

All of the above

update users collection and restart mongodb with -auth option

update users collection and run db.enableAuthenticationQ

27. Given a replica set with five data-bearing members, suppose the primary goes down with operations in its oplog that have been copied from the primary to only one secondary.

Assuming no other problems occur, which of the following describes what is most likely to happen?

missing operations will need to be manually re-performed

the secondary with the most current oplog will be elected primary

reads will be stale until the primary comes back up

the primary may roll back the operations once it recovers

the most current secondary will roll back the operations following the election

28. Which of the following is incorrect statement about find and findOne operations in MongoDB?

findQ returns all the documents in a collection while findOne() retrieves only the first one.

find.limit(l) is not the same query as findOne()

findOneQ returns the actual first document retrieved from a collection

findQ and findOneQ returns cursors to the collection documents

29. Which command is used to determine storage capacity of specific database?

mongotop

dbstats

mongostat

constats

30. In a collection that contains 100 post documents, what does the following command do? db. posts. find().skip(5).limit(5)

Skip and limit nullify each other. Hence returning the first five documents.

Skips the first five documents and returns the next five

Limits the first five documents and then return them in reverse order

Skips the first five documents and returns the sixth document five times

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31. 'mongoimport' command is used for

Batch data insertion

None of the above

Multiple command import

Multiple command insertion

32. Which format/standard is used by MongoDB internally to store documents?

JSON

BSON

B+ Trees

JSON - Extended

33. Which of the tags in a replica set configuration specify the operations to be read from the node with the least network latency?

netLatency

secondaryPreferred

nearest

primaryPreferred

34. The difference between $push and $addToSet is:

$addToSet needs the fields to be already present while $push will work even if the field is not present

$addToSet adds the item to the field only if it does not exist already; while $push pushes the item to the field irrespective of whether it was present or not

$addToSet adds the item to the field only if the new item is of the same datatype

There is no major difference between them. $addToSet is a deprecated version of $push.

35. Which of the following statements are true about the $match pipeline operator? Check all that apply.

You should use it early as possible in the pipeline

It can be used as many time as needed.

It has a sintax similar to findQ commands.

36. What is the maximum size of a MongoDB document

16 MB

12 MB

2 MB

There is no maximum size. It depends on the RA

37. What is the output of the following program?

60 s

100 s

100 ms

38. Which is the default mode in which the explain() command runs?

allPlansExecution

customExecutionStats

queryPlanner

executionStats

39. Which of the following operators is used to updated a document partially?

$set

$update

$project

$modify

40. Which of the following is a valid insert statement in mongodb? Select all valid.

db.test.push({x:2,y:"apple"})

db.test.insert«"x":2, "y":"apple"})

db.test.insert({x:2,y:"apple"})

db.test.insert({x:2},{y:"apple"})

C100DBA MongoDB Certified DBA Associate Exam Questions

C100DBA MongoDB Certified DBA Associate Exam Questions

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