R4RIN – MCQs, Mock Tests | MongoDB MongoDB Mcq Question Set 12

Which of the following returns a substring of a string?

1. $subs
2. $substring
3. $substr
4. None of the mentioned

✅ Correct Answer: 3

. Point out the correct statement.

1. $substr ends at a specified index position up to a specified length
2. $toLower converts a string to lowercase
3. $gtle returns true if the first value is greater than or equal to the second
4. All of the mentioned

✅ Correct Answer: 2

Which of the following accepts a single argument expression?

1. $toLow
2. $toUpper
3. $toEqual
4. None of the mentioned

✅ Correct Answer: 2

Which of the following performs case-insensitive string comparison?

1. $strcasecmpequals
2. $strcasecmp
3. $strcmp
4. None of the mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. { $meta: “textScore” } expression is only meaningful in a pipeline that includes a $match stage with a $text query
2. The { $meta: “textScore” } expression is the only expression that the $sort stage accepts
3. $toLower only has a well-defined behavior for strings of ASCII characters
4. None of the mentioned

✅ Correct Answer: 4

______ is used for access text search metadata.

1. $text
2. $metades
3. $meta
4. All of the Mentioned

✅ Correct Answer: 3

Which of the following accepts named parameters?

1. $reduce
2. $letnum
3. $let
4. None of the mentioned

✅ Correct Answer: 4

____ returns the number of elements in the array.

1. $number
2. $size
3. $div
4. None of the mentioned

✅ Correct Answer: 2

_____ returns a value without parsing.

1. $string
2. $literal
3. $characters
4. None of the mentioned

✅ Correct Answer: 2

db.collection.aggregate() returns a _______ and can return result sets of any size.

1. replica
2. cursor
3. document
4. $subtract

✅ Correct Answer: 2

The _____ JavaScript engine allows multiple JavaScript operations to execute at the same time.

1. V8
2. V12
3. V7
4. None of the mentioned

✅ Correct Answer: 1

Point out the correct statement.

1. The read phase takes a exclusive lock
2. The map-reduce operation is composed of many tasks
3. Prior to version 3, JavaScript code executed in a single thread
4. All of the mentioned

✅ Correct Answer: 2

If the ______ field for mapReduce has the sharded value, MongoDB shards the output collection using the _id field as the shard key.

1. input
2. $in
3. $out
4. None of the mentioned

✅ Correct Answer: 3

In MongoDB __________ mongos retrieves the results from each shard, performs a merge sort to order the results.

1. 3.0
2. 2.0
3. 1.0
4. None of the mentioned

✅ Correct Answer: 2

Point out the wrong statement.

1. If the output collection does not exist, MongoDB creates and shards the collection on the _id field
2. Map-reduce supports operations on sharded collections, both as an input and as an output
3. mongos dispatches, in parallel, a map-reduce post-processing job to every shard that owns a chunk
4. none of the mentioned

✅ Correct Answer: 4

Which of the following function follows the reduce method and modifies the output?

1. finalize
2. final
3. max
4. All of the mentioned

✅ Correct Answer: 1

______ specifies global variables that are accessible in the map.

1. jsMode
2. scope
3. finalize
4. Min

✅ Correct Answer: 2

MongoDB converts the JavaScript objects emitted by the map function to ________ objects.

1. BSON
2. JSON
3. Javascript
4. None of the mentioned

✅ Correct Answer: 1

You can only use jsMode for result sets with fewer than 500,000 distinct key arguments to the mapper’s _______ function.

1. emit()
2. emitter()
3. emitted()
4. none of the mentioned

✅ Correct Answer: 1

Which of the following mode defaults to false?

1. jsMode
2. scope
3. finalize
4. Min

✅ Correct Answer: 1

$dayOfMonth returns the day of the month for a date as a number between _____

1. 1 and 31
2. 1 and 30
3. 1 and 28
4. None of the mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. $second returns the seconds for a date as a number between 0 and 60 (leap seconds)
2. $minute returns the minute for a date as a number between 0 and 59
3. $millis returns the milliseconds of a date as a number between 0 and 1000
4. All of the mentioned

✅ Correct Answer: 3

_____ returns the day of the year for a date as a number between 1 and 366.

1. $dayofWeekend
2. $dayOfWeek
3. $dayOfYear
4. None of the mentioned

✅ Correct Answer: 3

Which of the following returns year for particular date?

1. $year
2. $yearday
3. $syearofmonth
4. None of the mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. $weekDay returns the week number for a date as a number between 0 and 53 (leap year)
2. $cond accepts either two expressions in an ordered list or three named parameters
3. $toLower only has a well-defined behavior for strings of ASCII characters
4. None of the mentioned

✅ Correct Answer: 2

Which of the following returns the hour for a date as a number between 0 and 23?

1. $minute
2. $hour
3. $seconds
4. All of the Mentioned

✅ Correct Answer: 2

______ returns the date as a formatted string.

1. $toString
2. $dateToString
3. $letString
4. None of the mentioned

✅ Correct Answer: 2

___ result encompasses instances of undefined values or missing fields.

1. Number
2. String
3. Null
4. None of the mentioned

✅ Correct Answer: 3

______ returns either the non-null result of the first expression.

1. $Null
2. $ifNull
3. $ElseNull
4. none of the mentioned

✅ Correct Answer: 2

______ take as input a single expression, evaluating the expression once for each input document, and maintain their state for the group of documents.

1. Computer
2. Monitors
3. Accumulators
4. Performoner

✅ Correct Answer: 3

$sum is an accumulator operator available only in the _______ stage.

1. $group
2. $sets
3. $accumulator
4. None of the mentioned

✅ Correct Answer: 1

Point out the wrong statement.

1. $avg is an accumulator operator available only in the $group stage
2. $sum accumulator can be used to compute the total amount and count for each group of documents
3. $avg ignores numeric values
4. All of the Mentioned

✅ Correct Answer: 3

Which of the following ignores non numeric values?

1. $order
2. $sum
3. $asc
4. None of the mentioned

✅ Correct Answer: 2

When using $first in a $group stage, the $group stage should follow a _______ stage to have the input documents in a defined order.

1. $order
2. $sort
3. $asc
4. None of the mentioned

✅ Correct Answer: 2

Which of the following returns the value that results from applying an expression to the last document?

1. $end
2. $last
3. $max
4. All of the Mentioned

✅ Correct Answer: 2

______ returns the highest value from the group of values in documents.

1. $end
2. $last
3. $max
4. $maximum

✅ Correct Answer: 3

Which of the following is syntax for calculating minimum value?

1. { $minimum: <int> }
2. { $min: <expression>}
3. { $minimum: <expression> }
4. None of the mentioned

✅ Correct Answer: 2

If all documents for the $min operation have null value for the field or are missing the field, the $min operator returns ____ for the minimum value.

1. 1
2. 0
3. null
4. none of the mentioned

✅ Correct Answer: 3

$addToSet returns an array of all _______ values that results from applying an expression to each document.

1. unique
2. non unique
3. distinct
4. All of the mentioned

✅ Correct Answer: 1

____ references the root document, i.e. the top-level document, currently being processed in the aggregation pipeline stage.

1. CURRENT
2. ROOT
3. PRUNE
4. All of the Mentioned

✅ Correct Answer: 2

Point out the wrong statement.

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

✅ Correct Answer: 4

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

1. $sort
2. $match
3. $sortby
4. none of the mentioned

✅ Correct Answer: 1

Which of the following provides similar functionality to join?

1. $unwindelem
2. $unwind
3. $unwin
4. None of the mentioned

✅ Correct Answer: 3

Point out the wrong statement.

1. CURRENT references the start of the field path being processed in the aggregation pipeline stage
2. All stages start with CURRENT the same as ROOT
3. DESCENDING is one of the allowed results of a $let expression
4. None of the mentioned

✅ Correct Answer: 3

_____ limits the number of documents in result set.

1. $project
2. $geo
3. $limit
4. none of the mentioned

✅ Correct Answer: 3

Which of the following is used to retrieve like SELECT clause in SQL?

1. $reduce
2. $select
3. $project
4. none of the mentioned

✅ Correct Answer: 3

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

1. $setcon
2. $group
3. $match
4. None of the mentioned

✅ Correct Answer: 2

______ works similar to HAVING clause in SQL.

1. $setcon
2. $group
3. $match
4. None of the mentioned

✅ Correct Answer: 3

COUNT function is provided by _________ in MongoDB.

1. $end
2. $sum
3. $max
4. All of the Mentioned

✅ Correct Answer: 2

MongoDB indexes use a _______ data structure.

1. Hash
2. Map
3. B-tree
4. All of the mentioned

✅ Correct Answer: 2