Question 1

What does the output x of the following MongoDB aggregation query result into; db.posts.aggregate( [ { $group: { _id; '$author', x: { $sum: $likes } } } ] )

Options :

A : Average of likes on all the posts of an author, grouped by author

B : Number of posts by an author

C : Sum of likes on all the posts by all the authors

D : Sum of likes on all the posts by an author, grouped by author

Answer: D

Question 2

By default, the MongoDB cursor in mongo shell is configured to return how many documents? To get the next set of documents, which command is used?

Options :

A : 200, more

B : No limit, none

C : 20, it

D : 50, it

Answer: C

Question 3

'mongoimport' command is used for

Options :

A : Batch data insertion

B : None of the above

C : Multiple command import

D : Multiple command insertion

Answer: A

Question 4

Which mongodb tools allow us to work with our data in a human readable format?

Options :

A : mongodump

B : mongostat

C : mongoimport

D : mongoexport

Answer: C,D

Question 5

Which of the following commands can cause the database to be locked?

Options :

A : All of the above

B : Inserting data

C : Map-reduce

D : Issuing a query

Answer: A