MongoDB Online Test

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_______ groups documents by some specified expression and outputs to the next stage a document for each distinct grouping

$setcon
$group
$match
None of the mentioned

Correct Answer : B

______ can be used to iterate the cursor of document results returned by db.collection.find()

it
next
cur
none of the mentioned

Correct Answer : A

Point out the wrong statement

Secondary indices are not available in MongoDB
MongoDB supports search by field, range queries, regular expression searches
MongoDB can store the business subject in the minimal number of documents
All of the mentioned

Correct Answer : A

The ________ message is used to update a document in a collection

UPDATE
OP_UPDATE
OP_UPDATES
All of the mentioned

Correct Answer : B

Which of the following preference determines how the client direct read operations to the set?

read
write
update
delete

Correct Answer : A

MongoDB is a _________ database that provides high performance, high availability, and easy scalability

graph
key value
document
all of the mentioned

Correct Answer : C

Which of the following method is used to query documents in collections?

find
move
shell
replace

Correct Answer : A

MongoDB applies the _____ phase to each input document in mapreduce.

map
reduce
mapper
all of the mentioned

Correct Answer : A

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

$match moves before $sort
$sort moves before $match
MongoDB does not do any movements by default and will use the order provided
Providing these parameters in any order does not impact the performance

Correct Answer : A

__________ returns the JavaScript representation in the form of a string literal

toStringJava()
toString()
String()
none of the mentioned

Correct Answer : B

A query may include a ___________ that specifies the fields from the matching documents to return

selection
projection
union
none of the mentioned

Correct Answer : B

To describe the message structure, a ________ like struct is used

Pascal
C++
C
Java

Correct Answer : C

Which of the following provides similar functionality to join?

$unwindelem
$unwind
$unwin
None of the mentioned

Correct Answer : C

Which of the operator is similar to order by clause in RDBMS?

$sort
$match
$sortby
None of the mentioned

Correct Answer : A

Which of the following functionality is used for aggregation framework?

$match
$project
$projectmatch
All of the mentioned

Correct Answer : B

A collection and a document in MongoDB is equivalent to which of the SQL concepts respectively?

Table and Row
Table and Column
Column and Row
Database and Table

Correct Answer : A

An index cannot cover a query on a _______ collection when run against a mongos if the index does not contain the shard key.

vertical
sharded
horizontal
none of the mentioned

Correct Answer : B

After starting the mongo shell, your session will use the ________ database by default

mongo
master
test
primary

Correct Answer : C

Which of the following flag can be set by mongo shell?

Timeout
noTimeout
Time
None of the mentioned

Correct Answer : B

____________ works similar to HAVING clause in SQL

$setcon
$group
$match
None of the mentioned

Correct Answer : C

Which index is used to index the content stored in arrays?

Multikey Index
Compound Index
Text Index
Sparse Index

Correct Answer : A

With a receipt acknowledged write concern, the _________confirms that it received the write operation and applied the change to the in-memory view of data

mongod
mongos
mongo
mongoc

Correct Answer : A

Which of the following will implicitly create the collection testData?

while (var i = 1; i <= 25; i++) 
{
     db.testData.insert( { x : i } )
}

for (var i = 1; i <= 25; i++) 
{
   db.testData.insert( { x : i } )
}

for (var i = 1; i <= 25; i++)
{
   db.testData.inserts( { x : i } )
}

None of the mentioned

Correct Answer : B

Point out the wrong statement

Variables can hold any BSON type data
Aggregation expressions can use both user-defined and system variables
To access the value of the variable, use a string with the variable name prefixed with double dollar signs ($$)
None of the mentioned

Correct Answer : C

The output of the reduce function may pass through a ______ function to further condense or process the results of the aggregation

finalize
filter
procedure
none of the mentioned

Correct Answer : A

Which of the following language is MongoDB written in?

Javascript
C
C++
All of the mentioned

Correct Answer : D

Which of the following mode defaults to false?

jsMode
scope
finalize
min

Correct Answer : A

_____________ is used to control mongod commits in the journal

commitIntervMs
commitInterval
commitIntervalMs
all of the mentioned

Correct Answer : C

Point out the correct statement

Queries specify criteria, or conditions, that identify the documents that MongoDB returns to the clients
Write operations, or queries, retrieve data stored in the database
The selection limits the amount of data that MongoDB returns to the client over the network
All of the mentioned

Correct Answer : A

What is the minimum sensible number of voting nodes to a replica set?

Correct Answer : B