MongoDB Online Quiz

Q 1 - Which of the following is correct about MongoDB?

A - MongoDB uses JSON format to represent documents

B - MongoDB supports collection joins

C - MongoDB supports some of the SQL functions

D - MongoDB supports geospatial indexes

Q 2 - What is the output of the following program?

A - 60 s

B - 100 ms

C - 1 s

D - 100 s

Q 3 - Consider that our posts collection contains an array field called tags that contains tags that the user enters.

{
            _id: 1,
            tags: [“tutorial”, “fun”, “learning”],
            post_text: “This is my first post”,	
            //other elements of document  	
} 

Which of the following commands will find all the posts that have been tagged as tutorial.

A - db.posts.find( { tags : "tutorial" } );

B - db.posts.find( { tags : ["tutorial"] } );

C - db.posts.find( { $array : {tags: "tutorial"} } );

D - db.posts.findInArray( { tags : "tutorial" } );

Q 4 - Which option should be used to update all the documents with the specified condition in the MongoDB query?

A - updateAll instead of update

B - specify {multi : true} as the third parameter of update command

C - specify {all: true} as the third parameter of update command

D - specify {updateAll: true} as the third parameter of update command

Q 5 - Which option should be used with findAndModify() command to return the modified document instead of the pre-modification document?

A - findAndModify by default returns the pre-modification document

B - Set {new : true}

C - Use the POST version of findAndModify called findAndModifyPost

D - Both b and c are valid

Q 6 - What is the default size of a GridFS chunk?

A - 16 MB

B - 255 K

C - 1 MB

D - 2 MB

Q 7 - Consider that you have a collection called population which has fields state and city. Which of the following query will calculate the population grouped by state and city?

A - db.population.aggregate( [{ $group: { _id: { state: "$state", city: "$city" },pop: { $sum: "$pop" } } }] )

B - db.population.aggregate( [{ $group: { _id: { state: "$state", city: "$city" },pop: { $sum: 1 } } }] )

C - db.population.aggregate( [{ $group: { _id: { state: "$state", city: "$city" },pop: { “$pop”: 1 } } }] )

D - db.population.aggregate( [{ $group: { _id: { city: "$city" },pop: { $sum: "$pop" } } }] )Multi Document Transaction is not supported by MongoDB

Q 8 - In a replica set, a ________ number of members ensures that the replica set is always able to select a primary.

A - Odd

B - Even

C - Depends on the application architecture

D - 2

Q 9 - We can insert multiple documents in bulk using which of the following operations:

A - initializeUnorderedBulkOp

B - initializeBulkOp

C - initializeBulk

D - initializeUnorderedBulk

Q 10 - What does the following $slice query return using the following command?

   
db.posts.find( {}, { comments: { $slice: [ -10, 5 ] } } )

A - Returns 5 comments, beginning with the last 10 items

B - Returns 10 comments, beginning with the first

C - Returns 10 comments, beginning with the last

D - Returns 5 comments, beginning with the first 10 items