MongoDB interview questions part 2
MongoDB interview questions part 2
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Total Questions: 20
1. Pipeline stages can use __________ for tasks such as calculating the average or concatenating a string.
Correct Answer is : operators
2. Map-reduce uses custom __________ functions to perform the map and reduce operations.
Correct Answer is : Javascript
3. Which of the following operation can be optionally used for map reduce ?
Correct Answer is : finally
4. The aggregation pipeline can use ___________ to improve its performance during some of its stages.
Correct Answer is : indexes
5. Pipeline stages can use __________ for tasks such as calculating the average or concatenating a string.
Correct Answer is : operators
6. Point out the wrong statement :
Correct Answer is : $limit groups output documents by a specified operator
7. To handle large datasets, set _________ option to true to enable writing data to temporary files.
Correct Answer is : allowDiskUse
8. ________ deconstructs an array field from the input documents to output a document for each element.
Correct Answer is : $unwin
9. Point out the wrong statement :
Correct Answer is : None of the mentioned
10. ________ applies an expression to each item in an array and returns an array with the applied results.
Correct Answer is : $map
11. Which of the following accepts named parameters ?
Correct Answer is : None of the mentioned
12. String expressions, with the exception of ________ only have a well-defined behavior for strings of ASCII characters.
Correct Answer is : $concat
13. ___________ returns either the non-null result of the first expression.
Correct Answer is : $ifNull
14. Which of the following returns the value that results from applying an expression to the last document ?
Correct Answer is : $last
15. Which of the following stages cannot appear multiple times in a pipeline ?
Correct Answer is : $match
16. Point out the correct statement :
Correct Answer is : Expressions can include field paths and system variables, literals, expression objects, and expression operators
17. Aggregation expressions use ______ path to access fields in the input documents.
Correct Answer is : field
18. Which of the following statement is equivalent to “$$CURRENT.“?
Correct Answer is : “$”
19. Point out the wrong statement:
Correct Answer is : CURRENT cannot be rebound
20. ______ binds variables for use in the specified expression.
Correct Answer is : $let
