Ultimate Guide to C100DBA Dumps - Enhance Your Future Career Now [Q39-Q56] : Exam for engine : http://blog.test4engine.com

QUESTION 39
Which of the following command is used to get all the indexes on a collection?

db.collection.showIndexes()

db.collection.findlndexes()

db.showIndexes()

db.collection.getlndexesQ

QUESTION 40
Update If Correct is an approach for which of the following concepts in MongoDB:

Concurrency Control

Atomicity

Performance Management

Transaction Management

QUESTION 41
Mongodb does provide high availability via which option?

Replication

Indexing

Sharding

Journaling

QUESTION 42
MongoDB is a schema-less design.

False

True

QUESTION 43
What is the maximum size of a MongoDB document

16 MB

12 MB

2 MB

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

QUESTION 44
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.

QUESTION 45
Addding the index {a:l} can potentially decrease the speed of which of the following operations? Check all that apply.

db.collection.update({b:456>, {$inc: {a:l> })

db.collection.find( {a : 232} )

db.collection.insert( { a:341})

QUESTION 46
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

QUESTION 47
You perform the following operation in the shell: db.foo.insert( { } ); What gets inserted?

A document will be inserted with the same _id as the last document inserted

A document that matches the collection’s existing schema, but with null fields

A document with an _id assigned to be an Objectld

An empty document

No document will be inserted; an error will be raised

QUESTION 48
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?

Switchover needs to be done manually

Failover happens automatically

Switchover happens automatically

Failover needs to be done manually

QUESTION 49
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?

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

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

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

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

QUESTION 50
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

QUESTION 51
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

QUESTION 52
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”;-!});

QUESTION 53
Which of the documents below will be retrieved by the following query? Assume the documents are stored in a collection called “sample”. Check all that apply.
db.sample.find( { “$or” : [ { “a” : { “$in” : [ 3, 10] > }, { “b” : { “$lt” : 2 > > ] > )

{”__id” :3, “a”: 4, “c” :0, “b” :14}

{”_Jd” :7, “a”: 8, “c” :1, “b” :7}

{“.Jd” :6, “a”: 1, “c” :1, “b” :5}

{ ”Jd” :9, “a”: 17, “c”: 1, “b”: 1}

{ Jd” :10,”a”: 3, “c”: 1, “b”: 1}

{“.Jd” :: 2, “a”: 2, “c” :: 0, “b”: 1}

{“.Jd” :: 4, “a”: 5, “c” :: 0, “b”: 17}

{“.Jd” :: 1, “a”: 0, “c” :: 0, “b”: 2}

{“.Jd” :: 5, “a”: 3, “c” :: 0, “b”: 12}

{“.Jd” :: 8, “a”: 11, “c”: 1, “b”: 0}

QUESTION 54
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?

QUESTION 55
What does the following aggregate query perform?

Fetches the posts with likes between 100 and 200 and sets their _id as null

Groups the posts by number of likes (101, 102, 103.) by adding 1 every time

Calculates the number of posts with likes between 100 and 200

Fetches the posts with likes between 100 and 200, sets the _id of the first document as null and then increments it 1 every time

QUESTION 56
What tool do you use if you want to extract a CSV from mongo?

Ultimate Guide to C100DBA Dumps - Enhance Your Future Career Now [Q39-Q56]

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