Free MongoDB C100DEV Exam Questions

Become MongoDB Certified with updated C100DEV exam questions and correct answers

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Total 411 Questions | Updated On: Mar 24, 2026

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Question 1

How can we present the basic syntax for aggregation in MongoDB?

A :

B :

C :

D :

Answer: D

Question 2

Consider a MongoDB collection named products which has documents in the following format:

{

"_id" : ObjectId("5f5b0d2f3e3dfbcc11c84444"),

"name" : "Smartphone",

"brand" : "Apple",

"category" : "Electronics",

"price" : 1000,

"discount" : 0.1

}

What is the correct syntax to update the "price" field of all documents in the products collection by multiplying it with (1 - discount) using the $set operator and the $multiply operator?

A : db.products.update( {}, { $set: { price: { $multiply: ["$price", { $subtract: [1, "$discount"] }] } } })

B : db.products.updateMany( {}, { $set: { price: { $multiply: ["$price", 1 - $discount] } } })

C : db.products.update( {}, { $set: { price: { $multiply: ["$price", 1 - $discount] } } })

D : db.products.updateMany( {}, { $set: { price: { $multiply: ["$price", { $subtract: [1, "$discount"] }] } } })

Answer: D

Question 3

Consider the following scenario: You have a MongoDB collection named users that stores user information. Each document in the collection has the following structure:

{

"_id": ObjectId("609fe4b5728ad805aef1a88d"),

"name": "John Doe",

"age": 30,

"email": "johndoe@example.com",

"address": {

"street": "123 Main St",

"city": "New York",

"state": "NY",

"zipcode": "10001"

}

You need to retrieve all the documents from the users collection and convert them to an array format. Which of the following MongoDB queries should you use for this task?

A : db.users.find().convertToArray()

B : db.users.find().toArray()

C : db.users.toArray()

D : db.users.aggregate({ $toArray: "users" })

Answer: B

Question 4

Suppose you have a restaurants collection with the following document structure:

{

_id: ObjectId("5eb3d668b31de5d588f42931"),

address: {

building: '6409',

coord: [ -74.00528899999999, 40.628886 ],

street: '11 Avenue',

zipcode: '11219'

borough: 'Brooklyn',

cuisine: 'American',

grades: [

{

date: ISODate("2014-07-18T00:00:00.000Z"),

grade: 'A',

score: 12

{

date: ISODate("2013-07-30T00:00:00.000Z"),

grade: 'A',

score: 12

{

date: ISODate("2013-02-13T00:00:00.000Z"),

grade: 'A',

score: 11

{ date: ISODate("2012-08-16T00:00:00.000Z"),

grade: 'A',

score: 2 },

{

date: ISODate("2011-08-17T00:00:00.000Z"),

grade: 'A',

score: 11

}

name: 'Regina Caterers',

restaurant_id: '40356649'

}

You don't have any indexes so far. What will the query plan look like for the following query?

db.restaurants.find( { "cuisine": "American" } )

A : IXSCAN

B : SORT

C : FETCH

D : COLLSCAN

Answer: D

Question 5

How does MongoDB handle sorting on fields that contain missing values (i.e., values that are not present in all documents in the collection)?

A : The behavior of sorting on missing values depends on the version of MongoDB being used.

B : The sort fails and returns an error.

C : Missing values are sorted first.

D : Missing values are sorted last.

Answer: C

Page: 1 / 83

Total 411 Questions | Updated On: Mar 24, 2026

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