Latest [May 22, 2023] MongoDB C100DEV Exam Practice Test To Gain Brilliante Result [Q116-Q137]

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Latest [May 22, 2023] MongoDB C100DEV Exam Practice Test To Gain Brilliante Result

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QUESTION 116
You have the following configuration file: net: bindIp: localhost port: 27000 security: authorization: enabled.
You have to edit this file to use new directory as the dbPath: /var/mongodb/db Select correct Answer .

dbPath: storage: /var/mongodb/db net: bindIp: localhost port: 27000 security: authorization: enabled

storage: dbPath: /data/db net: bindIp: localhost port: 27000 security: authorization: enabled

storage: dbPath: /var/mongodb/db net: bindIp: localhost port: 27000 security: authorization: enabled

QUESTION 117
What can you deduce from the explain() method?
For example:
db.collection.find().explain()

All stages that the query must go through with details about the time it takes, number of documents processed and returned to the next stage in the pipeline.

All available indexes for this collection.

The index used by the chosen plan.

Whether the sort stage was performed by index or performed in memory.

QUESTION 118
Select all true statements about replication in MongoDB.

It’s a good practice to have replicas in different geographical regions. If one region becomes unavailable due to a major failure in a data center or the network connection to it, the applications will continue to run without downtime.

Replication is also used to prevent downtime in the event of a failure in a data center.

QUESTION 119
Why is MongoDB using BSON instead of JSON to store data? Select all that apply.

BSON format is not human readable (BSON is machine-readable only).

BSON supports more data types than JSON.

BSON contains metadata to describe a document/object.

BSON simply means ‘Binary JSON’.

QUESTION 120
Consider a many-to-many relationship observed between courses and the students enrolled in these courses. Which of the following are true about modeling this many-to-many relationship with the document model in MongoDB?

Embedding students in courses duplicates student information.

Embedding students in courses still requires a separate collection to store all students (we may have students who are not enrolled in any course).

The many-to-many relationship cannot be represented in MongoDB.

When using one collection for students and one collection for courses there is a need for an array of references in only one collection.

QUESTION 121
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 movies that were made in 2000 or 2010?

db.movies.find( { $or: [ { year: 2000 }, { year: 2010 } ] } )

db.movies.find( { year: 2000, year: 2010 } )

db.movies.find( { $and: [ { year: 2000 }, { year: 2010 } ] } )

db.movies.find( { $in: [ { year: 2000 }, { year: 2010 } ] } )

QUESTION 122
Select all true statements regarding to the insert operation.

If you insert a document with no _id value specified, it will result in a write error.

If you insert document with a _id field value that already exists, an error will be raised.

MongoDB will automatically add an _id field when inserting document without specified _id field into a collection.

QUESTION 123
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 } } We need to use Aggregation Framework to fetch all movies from this collection where ‘Drama’ is not in genres list and the minimum ‘imdb.votes’ is at least 100. Additionally, in the projection stage, we want to leave only the following fields: -> title -> genres -> imdb.votes We also want to sort the result set by decreasing imdb votes and limit the number of documents retuned to 5. Example output: [ { imdb: { votes: 1294646 }, genres: [ ‘Action’, ‘Mystery’, ‘Sci-Fi’ ], title: ‘Inception’ }, { imdb: { votes: 1109724 }, genres: [ ‘Adventure’, ‘Fantasy’ ], title: ‘The Lord of the Rings: The Fellowship of the Ring’ }, { imdb: { votes: 1081144 }, genres: [ ‘Adventure’, ‘Fantasy’ ], title: ‘The Lord of the Rings: The Return of the King’ }, { imdb: { votes: 1080566 }, genres: [ ‘Action’, ‘Sci-Fi’ ], title: ‘The Matrix’ }, { imdb: { votes: 1004805 }, genres: [ ‘Action’, ‘Thriller’ ], title: ‘The Dark Knight Rises’ } ] Which pipeline should you use?

[{ $match: { genres: { $nin: [‘Drama’] }, ‘imdb.votes’: { $gte: 100 } } }, { $project: { _id: 0, title: 1, genres: 1, ‘imdb.votes’: 1 } }, { $sort: { ‘imdb.votes’: -1 } }, { $limit: 5 }]

[{ $match: { genres: { $in: [‘Drama’] }, ‘imdb.votes’: { $gte: 100 } } }, { $project: { _id: 0, title: 1, genres: 1, ‘imdb.votes’: 1 } }, { $sort: { ‘imdb.votes’: -1 } }, { $limit: 5 }]

[{ $match: { genres: { $nin: [‘Drama’] }, ‘imdb.votes’: { $gte: 100 } } }, { $project: { _id: 0, title: 1, genres: 1, ‘imdb.votes’: 1 } }, { $sort: { ‘imdb.votes’: -1 } }]

QUESTION 124
You have the following index in a movies collection: { “title”: 1, “imdb.rating”: -1, “imdb.votes”: -1, “type”: 1 } Can the following query use the given index for both filtering and sorting?
db.movies.find( { “title”: “James Bond”, “imdb.rating”: { “$gt”: 8} } ).sort( { “imdb.rating”: 1 } )

Yes

QUESTION 125
The users collection in the database is given. Which field will be the best candidate for an index in terms of cardinality?

gender (low cardinality)

age (medium cardinality)

email (high cardinality)

QUESTION 126
Suppose you have a developers collection with only two documents:
{ _id: 1, lname: ‘Smith’, tech_stack: [ ‘sql’, ‘git’, ‘python’, ‘django’ ], fname: ‘Bob’ }, { _id: 2, fname: ‘Michael’, lname: ‘Doe’, tech_stack: [ ‘git’, ‘python’, ‘sqlite’, ‘linux’, ‘flask’ ] }
Using Aggregation Framework you run the following stage:
{ $unwind: { path: ‘$tech_stack’ } }
How many documents will you have in the pipeline after the $unwind stage?

QUESTION 127
We have a restaurants collection with the following document structure: { _id: ObjectId(“5eb3d668b31de5d588f42a7d”), address: { building: ‘605’, coord: [ -74.0060152, 40.7372653 ], street: ‘Hudson Street’, zipcode: ‘10014’ }, cuisine: ‘French’, grades: [ { date: ISODate(“2014-06-30T00:00:00.000Z”), grade: ‘A’, score: 10 }, { date: ISODate(“2013-05-20T00:00:00.000Z”), grade: ‘A’, score: 13 }, { date: ISODate(“2012-12-11T00:00:00.000Z”), grade: ‘A’, score: 9 } ], name: ‘La Ripaille Restaurant’ } We need to use Aggregation Framework to calculate the total number of restaurants for top 5 cuisine (sorted in descending order by the number of restaurants). Expected output: [ { _id: ‘American’, total_restaurants: 6183 }, { _id: ‘Chinese’, total_restaurants: 2418 }, { _id: ‘Cafao/Coffee/Tea’, total_restaurants: 1214 }, { _id: ‘Pizza’, total_restaurants: 1163 }, { _id: ‘Italian’, total_restaurants: 1069 } ] Which pipeline should you use?

[{ $group: { _id: “$cuisine”, total_restaurants: { $sum: 1 } } }, { $sort: { total_restaurants: -1 } }, { $limit: 5 }]

[{ $group: { _id: “$cuisine”, total_restaurants: { $sum: 1 } } }, { $sort: { total_restaurants: 1 } }, { $limit: 5 }]

[{ $group: { _id: “$cuisine”, total_restaurants: { $sum: 1 } } }, { $limit: 5 }, { $sort: { total_restaurants: -1 } }]

[{ $group: { _id: “cuisine”, total_restaurants: { $sum: 1 } } }, { $sort: { total_restaurants: -1 } }, { $limit: 5 }]

QUESTION 128
Which of the following commands will add a collection that is stored in JSON file to a MongoDB cluster?

mongodump

mongoimport

mongostore

mongoexport

QUESTION 129
Select the method that forces MongoDB to use a specific index.

force()

explain()

hint()

index()

QUESTION 130
Suppose you have a companies collection in your database. Only the following documents are stored in this collection: { _id: ObjectId(“52cdef7c4bab8bd675297da4”), name: ‘Powerset’, category_code: ‘search’, founded_year: 2006 }, { _id: ObjectId(“52cdef7c4bab8bd675297da5”), name: ‘Technorati’, category_code: ‘advertising’, founded_year: 2002 }, { _id: ObjectId(“52cdef7c4bab8bd675297da7”), name: ‘AddThis’, category_code: ‘advertising’, founded_year: 2004 }, { _id: ObjectId(“52cdef7c4bab8bd675297da8”), name: ‘OpenX’, category_code: ‘advertising’, founded_year: 2008 }, { _id: ObjectId(“52cdef7c4bab8bd675297daa”), name: ‘Sparter’, category_code: ‘games_video’, founded_year: 2007 }, { _id: ObjectId(“52cdef7c4bab8bd675297dac”), name: ‘Veoh’, category_code: ‘games_video’, founded_year: 2004 }, { _id: ObjectId(“52cdef7c4bab8bd675297dae”), name: ‘Thoof’, category_code: ‘web’, founded_year: 2006 } How many documents will be returned in response to the following aggregation pipeline? [{ $group: { _id: ‘$category_code’, number_of_companies: { $sum: 1 } }}, { $sort: { number_of_companies: -1 }}, { $limit: 3 }]

QUESTION 131
Which of the following actions are granted to the built-in read role?

find

remove

insert

update

QUESTION 132
Assign typical operational tasks to the Data Scientist.

read data

write data

write data, read data

create user, create index

QUESTION 133
Select all true statements regarding to pipelines and the Aggregation Framework.

An aggregation pipeline consists of one or more stages that process documents.

The Aggregation Framework provides us many stages to filter and transform data.

The aggregation pipeline cannot operate on a sharded collection.

An aggregation pipeline is an array of stages.

Aggregation Framework does not have the group stage for grouping data.

QUESTION 134
Which of the following built-in roles provides the greatest cluster management access?

clusterManager

clusterMonitor

clusterAdmin

QUESTION 135
In your database there is a collection named trips with the following document structure: { ‘_id’: ObjectId(“572bb8222b288919b68abf6d”), ‘trip_duration’: 858, ‘start_station id’: 532, ‘end_station_id’: 401, ‘bike_id’: 17057, ‘start_station_location’: { type: ‘Point’, coordinates: [ -73.960876, 40.710451 ] }, ‘end_station_location’: { type: ‘Point’, coordinates: [ -73.98997825, 40.72019576 ] }, ‘start_time’: ISODate(“2016-01-01T00:09:31.000Z”), ‘stop_time’: ISODate(“2016-01-01T00:23:49.000Z”) } How can you extract all trips from this collection ended at stations that are to the west of the -73.5 longitude coordinate?

db.trips.find( { ‘coordinates’: { $lt: -73.5 } } )

db.trips.find( { ‘end_station_location.coordinates.0’: { $gt: -73.5 } } )

db.trips.find( { ‘end_station_location.coordinates.0’: { $lt: -73.5 } } )

db.trips.find( { ‘end_station_location.coordinates.1’: { $lt: -73.5 } } )

QUESTION 136
Select all true statements regarding to $out stage.

$out operator creates collections in the same database as the source collection.

All indexes on an existing collection are rebuilt when $out overwrites the collection.

$out operator must be the last stage in a pipeline.

$out operator will create a new empty collection or overwrite an existing collection if the pipeline raises an error.

$out operator will overwrite an existing collection if specified.

QUESTION 137
Select true statements about shard keys.

Shard keys are used to organize documents into chunks and shards, and mongos can use this to route queries.