Free MongoDB C100DEV Exam Questions

Question 1

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 2

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

Question 3

Given the following documents in a collection:

{ _id: 1, n: [1,2,5], p: 0.75, c: 'Green' },

{ _id: 2, n: 'Orange', p: 'Blue', c: 42, q: 14 },

{ _id: 3, n: [1,3,7], p: 0.85, c: 'Orange' }

Which two documents can successfully be added in the same collection? (Select two)

A : { _id: 1, n: [1,2,5], p: 0.75, c: 'Green' }

B : { _id: 2, n: [1,2,5], p: 0.75, c: 'Green' }

C : { _id: 6, n: [1,3,7], p: 0.85, c: 'Orange }

D : { _id: 5, n: [1,2,5], p: 0.75, c: 'Green' }

Answer: C,D

Question 4

We have the following indexes:

{ name: 1, founded_year: 1 }

{ tag_list: 1, is_active: 1 }

And the following documents:

{

_id: ObjectId("52cdef7c4bab8bd675297daa"),

name: "Sparter",

founded_year: 2007,

tag_list: ["gaming", "game", "wow"],

is_active: true

},

{

_id: ObjectId("52cdef7c4bab8bd675297da3"),

name: "Yahoo!",

founded_year: 1994,

tag_list: ["search", "webmail"],

is_active: true

}

Select the true statement.

A : There would be a total of 2 index keys created across all of these documents and indexes.

B : There would be a total of 7 index keys created across all of these documents and indexes.

C : There would be a total of 4 index keys created across all of these documents and indexes.

D : The number of index keys cannot be determined from the given data.

Answer: B

Question 5

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