[Jul-2022] 100% Actual C100DBA dumps Q&As with Explanations Verified & Correct Answers
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NEW QUESTION 32
Which command is used to determine storage capacity of specific database?
- A. constats
- B. dbstats
- C. mongostat
- D. mongotop
Answer: B
NEW QUESTION 33
Consider the following example document from the sample collection. All documents in this collection have the same schema.
Which of the following queries will replace this with the document.
- A. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 > , { "justOne" : true > ) / This operation cannot be done with a single query.
- B. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 , { "$unset" : [ "a" , "b" ] } } )
- C. db.sample.update( { "_id" : 3 > , { "_id" : 7 , "c" : 4 > )
- D. db.sample.update( { "_id" : 3 } , { "$set" : { "_id" : 7 , "c" : 4 > > )
Answer: B
NEW QUESTION 34
Which of the following is true of the mechanics of replication in MongoDB? Check all that apply.
- A. Operations on the primary are recorded in a capped collection called the oplog
- B. Clients read from the nearest member of a replica ser by default
- C. Members of a replica set may replicate data from any other data-bearing member of the set by default
Answer: A
NEW QUESTION 35
You are in a sharded cluster. What will you do prior to initiating backup in sharded cluster?
- A. db.stopserver()
- B. sh.stopBalancer()
- C. sh.stopserverQ
- D. db.stopBalancer()
Answer: B
NEW QUESTION 36
In a replicated cluster, which of the following node would only be used during an election?
- A. primary
- B. arbiter
- C. secondary
- D. hidden
Answer: B
NEW QUESTION 37
To add a new user and enable authentication in MongoDB, which of the following steps need be executed?
- A. update users collection and restart mongodb with -auth option
- B. update users collection and run db.enableAuthenticationQ
- C. All of the above
- D. update users collection and restart mongodb
Answer: A
NEW QUESTION 38
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?
- A. db.posts.createIndex({^commerits.author";-!});
- B. db.posts.createIndex({^comments.$.author":-l});
- C. db. posts.createIndex({^comments.author" :1});
Answer: A
NEW QUESTION 39
JSON stands for
- A. JavaScript Object Naming
- B. None of the above
- C. JavaScript Object Notation
- D. JavaScript Object Notice
Answer: C
NEW QUESTION 40
Consider that our posts collection contains an array field called tags that contains tags that the user enters. {
Which of the following commands will find all the posts that have been tagged as tutorial.
- A. db.posts.findInArray( { tags : "tutorial" > );
- B. db.posts.find( { tags : "tutorial" } );
- C. db.posts.find( { tags : ["tutorial"] } );
- D. db.posts.find( { $array : {tags: "tutorial") > );
Answer: B
NEW QUESTION 41
Consider the following example document:
{
"_id": Objectld("5360c0a0a655a60674680bbe"),
"user"
"login": "irOn"
"description": "Made of steel"
"date": ISODate("2014-04-30T09:16:45.836Z"),
}
>
and index creation command:
db.users.createlndex( { "user.login": 1, "user.date": -1 }, "mylndex" ) When performing the following query:
db.users.find( { "user.login": /Air.*/ },
{ "user":1, "_id":0 > ).sort( { "user.date":1 > )
which of the following statements correctly describe how MongoDB will handle the query? Check all that apply.
- A. MongoDB will need to do a table/collection scan to find matching documents
- B. As an indexed query using "mylndex" because field "user.login" is indexed
- C. As a covered query using "mylndex" because we are filtering out "_id" and only returning "user.login"
- D. None of the above
- E. As an optimized sort query (scanAndOrder = false) using "mylndex" because we are sorting on an indexed field
Answer: B
NEW QUESTION 42
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( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $sum: "$pop" } } }] )
- B. db.population.aggregate( [{ $group: { _id: { state: "$state", city: "$city" },pop: { $pop: 1 } } }] )
- C. db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB
- D. db.population.aggregate( [{ $group: { _id: { state: Estate", city: "$city" },pop: { $sum: 1 > > >] )
Answer: A
NEW QUESTION 43
Below is a sample document of "orders" collection
Answer:
Explanation:
$project
NEW QUESTION 44
As per the aggregation pipeline optimization concepts, if you have a $sort followed by a $match:
- A. $sort moves before $match
- B. $match moves before $sort
- C. Providing these parameters in any order does not impact the performance
- D. MongoDB does not do any movements by default and will use the order provided
Answer: B
NEW QUESTION 45
Which of the following is a valid Replica Set configuration if you want:
1-Have 3 copies of everything
2- That RS3 is never primary
2- That RSI and RS2 can be primary?
You had to see the different configurations, RS3 could be hidden or priority 0 (But not a referee because we need
3 replicas), while RSI and RS2 could NOT have priority 0 or be hidden or anything like that In a 4-member RS RSO , RSI, RS2 and RS3 + Referee, RSO (primary) falls after some write operations that have replicated RSI and RS2 (but NOT RS3), who can get up as the new primary?
The configuration comes and in it we see that RS2 has a hidden: true (or a priority: 0, (I don't remember)
- A. O arbiter
- B. RSO
- C. ORS2
- D. ORS1
- E. ORS3
Answer: D
NEW QUESTION 46
What tool do you use to see if you have a problem in the consumption of disk I / 0?
Answer:
Explanation:
Mongoperf
NEW QUESTION 47
Which of the following operator can be used to limit the number of documents in an array field of a document after an update is performed?
- A. $arrayLimit
- B. $removeFromSet
- C. None of the above
- D. $push along with $each, $sort and $slice
Answer: D
NEW QUESTION 48
Which of the following needs to be performed prior to initiate backup on a sharded cluster?
- A. sh.stopServer( )
- B. db.stopServer( )
- C. db.stopBalancer( )
- D. sh.stopBalancer( )
Answer: D
NEW QUESTION 49
Which of the following node is used during election in a replication cluster?
- A. primary
- B. arbiter
- C. secondary
- D. hidden
Answer: B
NEW QUESTION 50
What is the use of mongodump and mongorestore tools?
- A. replicate mongodb deployments
- B. performance tune mongodb deployment
- C. backup mongodb deployment
- D. audit mongodb deployment
Answer: C
NEW QUESTION 51
Suposse tou have the following collection with only 2 documents:
If you run an aggregation query and use { $unwind: "$traits" } as the first stage, how many documents will be passed to the next stage of the aggregation pipeline?
- A. 0
- B. 1
- C. 2
- D. 3
- E. 4
Answer: D
NEW QUESTION 52
Which of the following is true about sharding?
- A. We cannot change a shard key directly/automatically once it is set up
- B. Sharding is enabled at the database level
- C. A sharded environment does not support sorting functionality since the documents lie on various mongod instances
- D. Creating a sharded key automatically creates an index on the collection using that key
Answer: A
NEW QUESTION 53
In a sharded cluster, from which node does one stop the balancer process before initiating backup?
- A. config server node
- B. replicaset primary node
- C. mongos node
- D. Any node
Answer: C
NEW QUESTION 54
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