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: Jan 13, 2026

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Question 1

You are designing a MongoDB collection to store information about books in a library. Each book document should contain the following fields:title: The title of the book (string).authors: An array of author names (array of strings).published_date: The publication date of the book (ISODate).categories: An array of categories or genres the book belongs to (array of strings).copies: An array containing details about each copy of the book, where each copy has an availability_status (string), location (string), and borrowed_date (ISODate) if the book is currently borrowed.Given this requirement, which of the following schemas correctly represents the document model for this use case? (Select two)

A :

B :

C :

D :

E :

Answer: A,E

Question 2

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 3

When sharding a MongoDB collection, what is the main factor that determines the distribution of data across shards?

A : The location of the client issuing the query

B : The number of documents in the collection

C : The size of each document

D : The value of a shard key

Answer: D

Question 4

You are working on a MongoDB database for a library system. The system tracks book information in a Books collection. A typical document in this collection looks like this:

Original Document:

{

"_id": ObjectId("book_id"),

"title": "The Art of Computer Programming",

"author": "Donald Knuth",

"genres": ["Computer Science", "Algorithms"],

"published_year": 1968,

"copies_available": 3

}

You are asked to update the document by replacing it with the following document:

Updated Document:

{

"title": "The Art of Computer Programming",

"published_year": 1973

}

After this update, what will the final document in the database look like?

A : { "_id": ObjectId("book_id"), "title": "The Art of Computer Programming", "published_year": 1973}

B : { "_id": ObjectId("book_id"), "title": "The Art of Computer Programming", "author": "Donald Knuth", "genres": ["Computer Science", "Algorithms"], "published_year": 1973, "copies_available": 3}

C : { "title": "The Art of Computer Programming", "published_year": 1973, "author": "Donald Knuth"}

D : { "_id": ObjectId("book_id"), "title": "The Art of Computer Programming", "published_year": 1973, "genres": ["Computer Science"]}

Answer: A

Question 5

Consider the following situation: You are a MongoDB Developer and are currently working on an application that requires complex reporting on large amounts of data. The application stores its data in MongoDB, which has grown significantly. To maintain efficiency and manageability, you decide to use MongoDB views. You want to create a view "UsersView" that includes only username, email, and createdAt fields from the Users collection. Which of the following commands would you use?

A : db.createView("UsersView", "Users", [{$project: {username: 1, email: 1, createdAt: 1}}])

B : db.Users.createView("UsersView", {$project: {username: 1, email: 1, createdAt: 1}})

C : db.Users.createView("UsersView", "Users", [{$project: {username: 1, email: 1, createdAt: 1}}])

D : db.Users.createView("UsersView", [{$project: {username: 1, email: 1, createdAt: 1}}])

Answer: A

Page: 1 / 83

Total 411 Questions | Updated On: Jan 13, 2026

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