Free MongoDB C100DEV Exam Questions

Question 1

Given a movies collection where each document has the following structure:

{

_id: ObjectId('573a1390f29313caabcd60e4'),

genres: [ 'Short', 'Comedy', 'Drama' ],

title: 'The Immigrant',

year: 1917,

imdb: { rating: 7.8, votes: 4680, id: 8133 },

countries: [ 'USA' ]

}

Which of the following queries will find all the movies that have more votes than the year in which they were released?

A : db.movies.find({ $expr: { $gt: ["imdb.votes", "year"] } } )

B : db.movies.find({ $expr: { $lt: ["$imdb.votes", "$year"] } } )

C : db.movies.find({ $gt: ["$imdb.votes", "$year"] } )

D : db.movies.find({ $expr: { $gt: ["$imdb.votes", "$year"] } } )

Answer: D

Question 2

You are managing a MongoDB collection named orders, where each document represents an order. The documents contain the following fields:order_id (String): The unique identifier for the order.customer_name (String): The name of the customer who placed the order.total_amount (Number): The total amount of the order.status (String): The status of the order, which can be "pending," "shipped," or "delivered."items (Array of Strings): A list of items included in the order.You want to find all orders that meet the following criteria:The order has a total amount greater than $1000.The order status is either "pending" or "shipped."The order contains either "laptop" or "smartphone" in the list of items.Which of the following queries would return the correct documents?

A :

B :

C :

D :

Answer: D

Question 3

We have a movies collection with the following document structure:

{

_id: ObjectId("573a1390f29313caabcd6223"),

genres: [ 'Comedy', 'Drama', 'Family' ],

title: 'The Poor Little Rich Girl',

released: ISODate("1917-03-05T00:00:00.000Z"),

year: 1917,

imdb: { rating: 6.9, votes: 884, id: 8443 }

},

{

_id: ObjectId("573a13e3f29313caabdc08a4"),

genres: [ 'Horror', 'Thriller' ],

title: 'Mary Loss of Soul',

year: 2014,

imdb: { rating: '', votes: '', id: 2904798 }

}

We need to use Aggregation Framework to calculate the following aggregates:

average imdb rating

minimum imdb rating

maximum imdb rating

Expected output:

[

{

_id: null,

avg_rating: 6.6934040649367255,

min_rating: 1.6,

max_rating: 9.6

}

]

Please note that some documents have "" (empty string) for the field "imdb.rating". Exclude these documents before aggregation.

Which pipeline should you use?

A : [{ $match: { "imdb.rating": { $ne: "" } }}, { $group: { _id: null, avg_rating: { $avg: "imdb.rating" }, min_rating: { $min: "imdb.rating" }, max_rating: { $max: "imdb.rating" } }}]

B : [{ $group: { _id: null, avg_rating: { $avg: "$imdb.rating" }, min_rating: { $min: "$imdb.rating" }, max_rating: { $max: "$imdb.rating" } }}]

C : [{ $match: { "imdb.rating": { $ne: "" } }}, { $group: { _id: null, avg_rating: { $avg: "$imdb.rating" }, min_rating: { $min: "$imdb.rating" }, max_rating: { $max: "$imdb.rating" } }}]

D : [{ $match: { "imdb.rating": { $ne: "" } }}, { $group: { _id: null, avg_rating: { avg: "$imdb.rating" }, min_rating: { min: "$imdb.rating" }, max_rating: { max: "$imdb.rating" } }}]

Answer: C

Question 4

In a MongoDB database, you have a collection named orders that contains information about various product orders placed by customers. Each document in the collection has the following structure:

{

"customerID": "",

"orderID": "",

"product": "",

"quantity": ,

"price": ,

"date": "",

"status": ""

}

You are required to write an aggregation query that retrieves all orders placed by customers where the quantity of ordered items is greater than 100 and the status of the order is "delivered". Which of the following $match stages would you use to achieve this? Select the best option.

A : { "$match": { "quantity": { "$gt": 100 }, "status": "delivered" } }

B : { "$match": { "quantity": { "$lt": 100 }, "status": "delivered" } }

C : { "$match": { "quantity": { "$gt": 100 }, "status": { "$eq": "delivered" } } }

D : { "$match": { "quantity": { "$gte": 100 }, "status": "delivered" } }

Answer: A

Question 5

There is a collection named products in MongoDB database. Your coworker wants to know how many products are in this collection (number of documents in the collection). Which query should you use? (Select two)

A : db.products.total()

B : db.products.countAll()

C : db.products.countDocuments()

D : db.products.aggregate()

E : db.products.find().count()

Answer: C,E