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: Feb 19, 2026

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Question 1

In MongoDB, which statement accurately describes a typical task for a MongoDB developer related to schema validation?

A : Schema validation enables the creation of complex relationships between multiple collections.

B : Schema validation guarantees the uniqueness of a specific field across all documents in a collection.

C : Schema validation ensures the presence of required fields and their data types within a document.

D : Schema validation provides real-time data synchronization across multiple MongoDB instances.

Answer: C

Question 2

Suppose you have a reviews collection with the following index:

{ stars: 1, votes: 1 }

Which of the following queries would be a covered query?

A : db.reviews.find( { votes: { $gte: 100 } }, { _id: 0, votes: 1, stars: 1 })

B : db.reviews.find( { votes: { $gte: 100 } }, { _id: 0, votes: 1 })

C : db.reviews.find( { votes: { $gte: 100 }, stars: 4.5 }, { _id: 0 })

D : db.reviews.find( { stars: { $gt: 4.5 } }, { _id: 0, votes: 1 })

Answer: D

Question 3

You are developing a MongoDB application where write performance is a critical requirement. Given a scenario where your application primarily performs insert operations and rarely performs updates or deletes, which of the following MongoDB features would best optimize this heavy-write workload?

A : Change Streams

B : Capped Collections

C : Aggregation Pipeline

D : Sharding

Answer: D

Question 4

You are a MongoDB Associate Developer and need to demonstrate how to load the Atlas Sample Dataset into your MongoDB Atlas cluster. Your manager has asked you to guide a junior developer through this process to ensure they can independently load the dataset. What steps should the junior developer follow to successfully load the Atlas Sample Dataset?

A : In MongoDB Atlas, navigate to the "Clusters" tab, click on the "Load Sample Dataset" button, and wait for the dataset to be fully loaded.

B : In MongoDB Compass, connect to your cluster, go to the "Import Data" tab, and import the sample dataset by uploading the sample-dataset.json file.

C : Use the MongoDB Atlas API to send a POST request to the /loadSampleDataset endpoint, specifying your cluster ID in the request body.

D : Open the MongoDB Shell, connect to your cluster, and run the command mongoimport --db sample --collection datasets --file sample-dataset.json.

Answer: A

Question 5

Consider a collection named students with the following document:

{

"_id" : ObjectId("5f0a7e80d8c9c7b5a48c49e1"),

"name" : "Alice",

"age" : 21,

"courses" : [

{

"name" : "Math",

"grade" : 89

{

"name" : "Science",

"grade" : 92

}

]

}

What is the query to update the grade of the "Math" course for the student with "_id" equal to ObjectId("5f0a7e80d8c9c7b5a48c49e1") to 95?

A : db.students.updateOne( { "courses.name": "Math" }, { $set: { "courses.$.grade": 95 } })

B : db.students.updateOne( { _id: ObjectId("5f0a7e80d8c9c7b5a48c49e1") }, { $set: { "courses.$.grade": 95 } })

C : db.students.updateOne( { _id: ObjectId("5f0a7e80d8c9c7b5a48c49e1"), "courses.name": "Math" }, { $set: { "courses.$.grade": 95 } })

D : db.students.updateOne( { _id: ObjectId("5f0a7e80d8c9c7b5a48c49e1"), "courses.name": "Math" }, { $set: { "grade": 95 } })

Answer: C

Page: 1 / 83

Total 411 Questions | Updated On: Feb 19, 2026

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