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 29, 2026

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Question 1

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

{

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

"orderId" : 1001,

"customerId" : 200,

"items" : [

{

"productId" : 101,

"quantity" : 2

{

"productId" : 102,

"quantity" : 1

}

"totalAmount" : 250,

"status" : "Pending"

}

What is the correct syntax to find and update the first document in the orders collection where "status" is "Pending", and change the "status" field to "Completed" using the findAndModify method?

A : db.orders.findAndModify( { status: "Pending" }, { $set: { status: "Completed" } })

B : db.orders.findAndModify({ query: { status: "Pending" }, update: { $set: { status: "Completed" } }})

C : db.orders.findAndModify({ query: { status: "Pending" }, status: "Completed" })

D : db.orders.findAndModify({ status: "Pending" }, { status: "Completed" })

Answer: B

Question 2

Which of the following is the best practice for managing MongoDB data growth in a production environment (scale-out)?

A : Increasing the RAM size of the existing server.

B : Using replication.

C : Sharding the data across multiple servers.

D : Adding more disk space to the existing server.

Answer: C

Question 3

You manage a MongoDB collection called inventory that stores documents for a store's inventory. Each document has the fields item, category, and quantity. You want to ensure that an item is always present in the collection, even if it needs to be inserted. Specifically, if the item "notebook" in the "Stationery" category does not exist, it should be inserted with a quantity of 50. If it does exist, its quantity should be updated to 50. You plan to use the following command:

db.inventory.updateOne(

{ "item": "notebook", "category": "Stationery" },

{ $set: { "quantity": 50 } },

{ upsert: true }

)

What will happen after executing this command if there is no "notebook" item in the "Stationery" category in the inventory collection?

A : A new document will be inserted with only quantity: 50, as other fields (item and category) are not mentioned in the $set operator.

B : Nothing will happen because the $set operator only updates existing documents and cannot insert new ones.

C : A new document will be inserted with quantity: 50, but the item field will be set to null.

D : A new document will be inserted with item: "notebook", category: "Stationery", and quantity: 50.

Answer: D

Question 4

What is the correct syntax to insert multiple documents into a MongoDB collection named orders and return the _id values for all inserted documents?

A :

B :

C :

D :

Answer: B

Question 5

In a MongoDB collection named orders, you are tasked with retrieving a subset of documents that fulfill specific criteria. Each document in this collection contains the following fields: customerId, orderId, orderDate, and orderDetails (an embedded document with fields: product, quantity, unitPrice). You are required to fetch all orders made by the customer with a customerId of 1234 on a specific date 2023-04-12, and only return the orderId, orderDate, and product from orderDetails. Which of the following MongoDB queries would accurately fulfill these requirements?

A :

B :

C :

D :

Answer: A

Page: 1 / 83

Total 411 Questions | Updated On: Jan 29, 2026

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